Prepare Interview

Mock Exams

Make Homepage

Bookmark this page

Subscribe Email Address
Withoutbook LIVE Mock Interviews
The Best LIVE Mock Interview - You should go through before Interview
Test your skills through the online practice test: C++ Quiz Online Practice Test

Freshers / Beginner level questions & answers

Ques 1. What is C++?

Released in 1985, C++ is an object-oriented programming language created by Bjarne Stroustrup. C++ maintains almost all aspects of the C language, while simplifying memory management and adding several features - including a new datatype known as a class (you will learn more about these later) - to allow object-oriented programming. C++ maintains the features of C which allowed for low-level memory access but also gives the programmer new tools to simplify memory management.

C++ used for:

C++ is a powerful general-purpose programming language. It can be used to create small programs or large applications. It can be used to make CGI scripts or console-only DOS programs. C++ allows you to create programs to do almost anything you need to do. The creator of C++, Bjarne Stroustrup, has put together a partial list of applications written in C++.

Is it helpful? Add Comment View Comments
 

Ques 2. How do you find out if a linked-list has an end? (i.e. the list is not a cycle)

You can find out by using 2 pointers. One of them goes 2 nodes each time. The second one goes at 1 nodes each time. If there is a cycle, the one that goes 2 nodes each time will eventually meet the one that goes slower. If that is the case, then you will know the linked-list is a cycle.

Is it helpful? Add Comment View Comments
 

Ques 3. What is the difference between realloc() and free()?


The free subroutine frees a block of memory previously allocated by the malloc subroutine. Undefined results occur if the Pointer parameter is not a valid pointer. If the Pointer parameter is a null value, no action will occur. The realloc subroutine changes the size of the block of memory pointed to by the Pointer parameter to the number of bytes specified by the Size parameter and returns a new pointer to the block. The pointer specified by the Pointer parameter must have been created with the malloc, calloc, or realloc subroutines and not been deallocated with the free or realloc subroutines. Undefined results occur if the Pointer parameter is not a valid pointer.

Is it helpful? Add Comment View Comments
 

Ques 4. What is function overloading and operator overloading?

An overloaded declaration is a declaration that had been declared with the same name as a previously declared declaration in the same scope, except that both declarations have different arguments and obviously different definition (implementation).

When you call an overloaded function or operator, the compiler determines the most appropriate definition to use by comparing the argument types you used to call the function or operator with the parameter types specified in the definitions. The process of selecting the most appropriate overloaded function or operator is called overload resolution.

Function Overloading:
You can have multiple definitions for the same function name in the same scope. The definition of the function must differ from each other by the types and/or the number of arguments in the argument list. You can not overload function declarations that differ only by return type.

Operator Overloading:
You can redefine or overload most of the built-in operators available in C++. Thus a programmer can use operators with user-defined types as well.
Overloaded operators are functions with special names the keyword operator followed by the symbol for the operator being defined. Like any other function, an overloaded operator has a return type and a parameter list.

Is it helpful? Add Comment View Comments
 

Ques 5. What is the difference between declaration and definition?


The declaration tells the compiler that at some later point we plan to present the definition of this declaration.
E.g.: void stars () //function declaration
The definition contains the actual implementation.
E.g.: void stars () // declarator
{
for(int j=10; j > =0; j--) //function body
cout << *;
cout << endl; }

Is it helpful? Add Comment View Comments
 

Ques 6. What are the advantages of inheritance?


It permits code reusability. Reusability saves time in program development. It encourages the reuse of proven and debugged high-quality software, thus reducing problem after a system becomes functional.

Is it helpful? Add Comment View Comments
 

Ques 7. How do you write a function that can reverse a linked-list?


void reverselist(void)
{
if(head==0)
return;
if(head->next==0)
return;
if(head->next==tail)
{
head->next = 0;
tail->next = head;
}
else
{
node* pre = head;
node* cur = head->next;
node* curnext = cur->next;
head->next = 0;
cur-> next = head;

for(; curnext!=0; )
{
cur->next = pre;
pre = cur;
cur = curnext;
curnext = curnext->next;
}

curnext->next = cur;
}
}

Is it helpful? Add Comment View Comments
 

Ques 8. What do you mean by inline function?

The idea behind inline functions is to insert the code of a called function at the point where the function is called. If done carefully, this can improve the application's performance in exchange for increased compile time and possibly (but not always) an increase in the size of the generated binary executables.

Is it helpful? Add Comment View Comments
 

Ques 9. Write a program that ask for user input from 5 to 9 then calculate the average


#include "iostream.h"
int main() {
int MAX = 4;
int total = 0;
int average;
int numb;
for (int i=0; i<MAX; i++) {
cout << "Please enter your input between 5 and 9: ";
cin >> numb;
while ( numb<5 || numb>9) {
cout << "Invalid input, please re-enter: ";
cin >> numb;
}
total = total + numb;
}
average = total/MAX;
cout << "The average number is: " << average << "n";
return 0;
}

Is it helpful? Add Comment View Comments
 

Ques 10. Write a short code using C++ to print out all odd number from 1 to 100 using a for loop


for( unsigned int i = 1; i < = 100; i++ )
if( i & 0x00000001 )
cout << i << ",";
 

Is it helpful? Add Comment View Comments
 

Ques 11. What is public, protected, private?

Public, protected and private are three access specifier in C++.
Public data members and member functions are accessible outside the class.
Protected data members and member functions are only available to derived classes.
Private data members and member functions can?t be accessed outside the class. However there is an exception can be using friend classes.
Write a function that swaps the values of two integers, using int* as the argument type.
void swap(int* a, int*b) {
int t;
t = *a;
*a = *b;
*b = t;
}

Is it helpful? Add Comment View Comments
 

Ques 12. Tell how to check whether a linked list is circular.


Create two pointers, each set to the start of the list. Update each as follows:

Is it helpful? Add Comment View Comments
 

Ques 13. OK, why does this work?


If a list is circular, at some point pointer2 will wrap around and be either at the item just before pointer1, or the item before that. Either way, it?s either 1 or 2 jumps until they meet.

Is it helpful? Add Comment View Comments
 

Ques 14. What is virtual constructors/destructors?


Answer1
Virtual destructors:
If an object (with a non-virtual destructor) is destroyed explicitly by applying the delete operator to a base-class pointer to the object, the base-class destructor function (matching the pointer type) is called on the object.
There is a simple solution to this problem declare a virtual base-class destructor.
This makes all derived-class destructors virtual even though they don?t have the same name as the base-class destructor. Now, if the object in the hierarchy is destroyed explicitly by applying the delete operator to a base-class pointer to a derived-class object, the destructor for the appropriate class is called. Virtual constructor: Constructors cannot be virtual. Declaring a constructor as a virtual function is a syntax error.

Answer2
Virtual destructors: If an object (with a non-virtual destructor) is destroyed explicitly by applying the delete operator to a base-class pointer to the object, the base-class destructor function (matching the pointer type) is called on the object.
There is a simple solution to this problem ? declare a virtual base-class destructor. This makes all derived-class destructors virtual even though they don?t have the same name as the base-class destructor. Now, if the object in the hierarchy is destroyed explicitly by applying the delete operator to a base-class pointer to a derived-class object, the destructor for the appropriate class is called.

Is it helpful? Add Comment View Comments
 

Ques 15. Virtual constructor: Constructors cannot be virtual. Declaring a constructor as a virtual function is a syntax error. Does c++ support multilevel and multiple inheritance?


Yes.

Is it helpful? Add Comment View Comments
 

Ques 16. What are the advantages of inheritance?


? It permits code reusability.
? Reusability saves time in program development.
? It encourages the reuse of proven and debugged high-quality software, thus reducing problem after a system becomes functional.

Is it helpful? Add Comment View Comments
 

Ques 17. What is the difference between declaration and definition?


The declaration tells the compiler that at some later point we plan to present the definition of this declaration.
E.g.: void stars () //function declaration
The definition contains the actual implementation.
E.g.: void stars () // declarator
{
for(int j=10; j>=0; j--) //function body
cout<<?*?;
cout<<endl; }

Is it helpful? Add Comment View Comments
 

Ques 18. What is the difference between an ARRAY and a LIST?

Answer1
Array is collection of homogeneous elements.
List is collection of heterogeneous elements.

For Array memory allocated is static and continuous.
For List memory allocated is dynamic and Random.

Array: User need not have to keep in track of next memory allocation.
List: User has to keep in Track of next location where memory is allocated.

Answer2
Array uses direct access of stored members, list uses sequencial access for members.

//With Array you have direct access to memory position 5
Object x = a[5]; // x takes directly a reference to 5th element of array

//With the list you have to cross all previous nodes in order to get the 5th node:
list mylist;
list::iterator it;

for( it = list.begin() ; it != list.end() ; it++ )
{
if( i==5)
{
x = *it;
break;
}
i++;
}

Is it helpful? Add Comment View Comments
 

Ques 19. Does c++ support multilevel and multiple inheritance?


Yes.

Is it helpful? Add Comment View Comments
 

Ques 20. What is a template?


Templates allow to create generic functions that admit any data type as parameters and return value without having to overload the function with all the possible data types. Until certain point they fulfill the functionality of a macro. Its prototype is any of the two following ones:


template <class indetifier> function_declaration; template <typename indetifier> function_declaration;
The only difference between both prototypes is the use of keyword class or typename, its use is indistinct since both expressions have exactly the same meaning and behave exactly the same way.

Is it helpful? Add Comment View Comments
 

Ques 21. Define a constructor - What it is and how it might be called

(2 methods).
Answer1
constructor is a member function of the class, with the name of the function being the same as the class name. It also specifies how the object should be initialized.

Ways of calling constructor:
1) Implicitly: automatically by complier when an object is created.
2) Calling the constructors explicitly is possible, but it makes the code unverifiable.

Answer2
class Point2D{
int x; int y;
public Point2D() : x(0) , y(0) {} //default (no argument) constructor
};

main(){

Point2D MyPoint; // Implicit Constructor call. In order to allocate memory on stack, the default constructor is implicitly called.

Point2D * pPoint = new Point2D(); // Explicit Constructor call. In order to allocate memory on HEAP we call the default constructor.
 

Is it helpful? Add Comment View Comments
 

Ques 22. What is the difference between class and structure?


Answer1
1.) ?new and delete? are preprocessors while ?malloc() and free()? are functions. [we dont use brackets will calling new or delete].
2.) no need of allocate the memory while using ?new? but in ?malloc()? we have to use ?sizeof()?.
3.) ?new? will initlize the new memory to 0 but ?malloc()? gives random value in the new alloted memory location [better to use calloc()]

Answer2
new() allocates continous space for the object instace
malloc() allocates distributed space.
new() is castless, meaning that allocates memory for this specific type,
malloc(), calloc() allocate space for void * that is cated to the specific class type pointer.
 

Is it helpful? Add Comment View Comments
 

Ques 23. What is RTTI?

Runtime type identification (RTTI) lets you find the dynamic type of an object when you have only a pointer or a reference to the base type. RTTI is the official way in standard C++ to discover the type of an object and to convert the type of a pointer or reference (that is, dynamic typing). The need came from practical experience with C++. RTTI replaces many Interview Questions - Homegrown versions with a solid, consistent approach.

Is it helpful? Add Comment View Comments
 

Ques 24. What is encapsulation?


Packaging an object?s variables within its methods is called encapsulation.

Is it helpful? Add Comment View Comments
 

Ques 25. Explain term POLIMORPHISM and give an example using eg. SHAPE object: If I have a base class SHAPE, how would I define DRAW methods for two objects CIRCLE and SQUARE



Answer1
POLYMORPHISM : A phenomenon which enables an object to react differently to the same function call.
in C++ it is attained by using a keyword virtual

Example
public class SHAPE
{
public virtual void SHAPE::DRAW()=0;
}
Note here the function DRAW() is pure virtual which means the sub classes must implement the DRAW() method and SHAPE cannot be instatiated

public class CIRCLE::public SHAPE
{
public void CIRCLE::DRAW()
{
// TODO drawing circle
}
}
public class SQUARE::public SHAPE
{
public void SQUARE::DRAW()
{
// TODO drawing square
}
}
now from the user class the calls would be like
globally
SHAPE *newShape;

When user action is to draw
public void MENU::OnClickDrawCircle(){
newShape = new CIRCLE();
}

public void MENU::OnClickDrawCircle(){
newShape = new SQUARE();

}

the when user actually draws
public void CANVAS::OnMouseOperations(){
newShape->DRAW();
}


Answer2
class SHAPE{
public virtual Draw() = 0; //abstract class with a pure virtual method
};

class CIRCLE{
public int r;
public virtual Draw() { this->drawCircle(0,0,r); }
};

class SQURE
public int a;
public virtual Draw() { this->drawRectangular(0,0,a,a); }
};

Each object is driven down from SHAPE implementing Draw() function in its own way.

Is it helpful? Add Comment View Comments
 

Ques 26. What is an object?


Object is a software bundle of variables and related methods. Objects have state and behavior.

Is it helpful? Add Comment View Comments
 

Ques 27. How can you tell what shell you are running on UNIX system?


You can do the Echo $RANDOM. It will return a undefined variable if you are from the C-Shell, just a return prompt if you are from the Bourne shell, and a 5 digit random numbers if you are from the Korn shell. You could also do a ps -l and look for the shell with the highest PID.

Is it helpful? Add Comment View Comments
 

Ques 28. What do you mean by inheritance?


Inheritance is the process of creating new classes, called derived classes, from existing classes or base classes. The derived class inherits all the capabilities of the base class, but can add embellishments and refinements of its own.

Is it helpful? Add Comment View Comments
 

Ques 29. Describe PRIVATE, PROTECTED and PUBLIC ? the differences and give examples.

class Point2D{
int x; int y;

public int color;
protected bool pinned;
public Point2D() : x(0) , y(0) {} //default (no argument) constructor
};

Point2D MyPoint;

You cannot directly access private data members when they are declared (implicitly) private:

MyPoint.x = 5; // Compiler will issue a compile ERROR
//Nor yoy can see them:
int x_dim = MyPoint.x; // Compiler will issue a compile ERROR

On the other hand, you can assign and read the public data members:

MyPoint.color = 255; // no problem
int col = MyPoint.color; // no problem

With protected data members you can read them but not write them: MyPoint.pinned = true; // Compiler will issue a compile ERROR

bool isPinned = MyPoint.pinned; // no problem

Is it helpful? Add Comment View Comments
 

Ques 30. What is namespace?


Namespaces allow us to group a set of global classes, objects and/or functions under a name. To say it somehow, they serve to split the global scope in sub-scopes known as namespaces.
The form to use namespaces is:
namespace identifier { namespace-body }
Where identifier is any valid identifier and namespace-body is the set of classes, objects and functions that are included within the namespace. For example:
namespace general { int a, b; } In this case, a and b are normal variables integrated within the general namespace. In order to access to these variables from outside the namespace we have to use the scope operator ::. For example, to access the previous variables we would have to put:
general::a general::b
The functionality of namespaces is specially useful in case that there is a possibility that a global object or function can have the same name than another one, causing a redefinition error.

Is it helpful? Add Comment View Comments
 

Ques 31. What is a COPY CONSTRUCTOR and when is it called?


A copy constructor is a method that accepts an object of the same class and copies it?s data members to the object on the left part of assignement:

class Point2D{
int x; int y;

public int color;
protected bool pinned;
public Point2D() : x(0) , y(0) {} //default (no argument) constructor
public Point2D( const Point2D & ) ;
};

Point2D::Point2D( const Point2D & p )
{
this->x = p.x;
this->y = p.y;
this->color = p.color;
this->pinned = p.pinned;
}

main(){
Point2D MyPoint;
MyPoint.color = 345;
Point2D AnotherPoint = Point2D( MyPoint ); // now AnotherPoint has color = 345

Is it helpful? Add Comment View Comments
 

Ques 32. What is Boyce Codd Normal form?


A relation schema R is in BCNF with respect to a set F of functional dependencies if for all functional dependencies in F+ of the form a-> , where a and b is a subset of R, at least one of the following holds:
* a- > b is a trivial functional dependency (b is a subset of a)
* a is a superkey for schema R

Is it helpful? Add Comment View Comments
 

Ques 33. What is virtual class and friend class?


Friend classes are used when two or more classes are designed to work together and need access to each other's implementation in ways that the rest of the world shouldn't be allowed to have. In other words, they help keep private things private. For instance, it may be desirable for class DatabaseCursor to have more privilege to the internals of class Database than main() has.

Is it helpful? Add Comment View Comments
 

Ques 34. What is the word you will use when defining a function in base class to allow this function to be a polimorphic function?


virtual
 

Is it helpful? Add Comment View Comments
 

Ques 35. What do you mean by binding of data and functions?


Encapsulation.

Is it helpful? Add Comment View Comments
 

Ques 36. What are 2 ways of exporting a function from a DLL?

1.Taking a reference to the function from the DLL instance.
2. Using the DLL ?s Type Library

Is it helpful? Add Comment View Comments
 

Ques 37. What is the difference between an object and a class?


Classes and objects are separate but related concepts. Every object belongs to a class and every class contains one or more related objects.
- A Class is static. All of the attributes of a class are fixed before, during, and after the execution of a program. The attributes of a class don't change.
- The class to which an object belongs is also (usually) static. If a particular object belongs to a certain class at the time that it is created then it almost certainly will still belong to that class right up until the time that it is destroyed.
- An Object on the other hand has a limited lifespan. Objects are created and eventually destroyed. Also during that lifetime, the attributes of the object may undergo significant change.

Is it helpful? Add Comment View Comments
 

Ques 38. Suppose that data is an array of 1000 integers. Write a single function call that will sort the 100 elements data [222] through data [321].


quicksort ((data + 222), 100);

Is it helpful? Add Comment View Comments
 

Ques 39. What is a class?


Class is a user-defined data type in C++. It can be created to solve a particular kind of problem. After creation the user need not know the specifics of the working of a class.

Is it helpful? Add Comment View Comments
 

Ques 40. What is friend function?


As the name suggests, the function acts as a friend to a class. As a friend of a class, it can access its private and protected members. A friend function is not a member of the class. But it must be listed in the class definition.

Is it helpful? Add Comment View Comments
 

Ques 41. Which recursive sorting technique always makes recursive calls to sort subarrays that are about half size of the original array?


Mergesort always makes recursive calls to sort subarrays that are about half size of the original array, resulting in O(n log n) time.

Is it helpful? Add Comment View Comments
 

Ques 42. What is abstraction?


Abstraction is of the process of hiding unwanted details from the user.

Is it helpful? Add Comment View Comments
 

Ques 43. What are virtual functions?


A virtual function allows derived classes to replace the implementation provided by the base class. The compiler makes sure the replacement is always called whenever the object in question is actually of the derived class, even if the object is accessed by a base pointer rather than a derived pointer. This allows algorithms in the base class to be replaced in the derived class, even if users don't know about the derived class.

Is it helpful? Add Comment View Comments
 

Ques 44. What is the difference between an external iterator and an internal iterator? Describe an advantage of an external iterator.


An internal iterator is implemented with member functions of the class that has items to step through. .An external iterator is implemented as a separate class that can be "attach" to the object that has items to step through. .An external iterator has the advantage that many difference iterators can be active simultaneously on the same object.
 

Is it helpful? Add Comment View Comments
 

Ques 45. What is a scope resolution operator?


A scope resolution operator (::), can be used to define the member functions of a class outside the class.

Is it helpful? Add Comment View Comments
 

Ques 46. What do you mean by pure virtual functions?


A pure virtual member function is a member function that the base class forces derived classes to provide. Normally these member functions have no implementation. Pure virtual functions are equated to zero.
class Shape { public: virtual void draw() = 0; };

Is it helpful? Add Comment View Comments
 

Ques 47. What is polymorphism? Explain with an example?


"Poly" means "many" and "morph" means "form". Polymorphism is the ability of an object (or reference) to assume (be replaced by) or become many different forms of object.
Example: function overloading, function overriding, virtual functions. Another example can be a plus ?+? sign, used for adding two integers or for using it to concatenate two strings.

Is it helpful? Add Comment View Comments
 

Ques 48. What?s the output of the following program? Why?

#include <stdio.h>
main()
{
typedef union
{
int a;
char b[10];
float c;
}
Union;

Union x,y = {100};
x.a = 50;
strcpy(x.b,"hello");
x.c = 21.50;

printf("Union x : %d %s %f n",x.a,x.b,x.c );
printf("Union y :%d %s%f n",y.a,y.b,y.c);
}

Given inputs X, Y, Z and operations | and & (meaning bitwise OR and AND, respectively)
What is output equal to in
output = (X & Y) | (X & Z) | (Y & Z)

Is it helpful? Add Comment View Comments
 

Ques 49. Why are arrays usually processed with for loop?


The real power of arrays comes from their facility of using an index variable to traverse the array, accessing each element with the same expression a[i]. All the is needed to make this work is a iterated statement in which the variable i serves as a counter, incrementing from 0 to a.length -1. That is exactly what a loop does.

Is it helpful? Add Comment View Comments
 

Ques 50. What is an HTML tag?


Answer: An HTML tag is a syntactical construct in the HTML language that abbreviates specific instructions to be executed when the HTML script is loaded into a Web browser. It is like a method in Java, a function in C++, a procedure in Pascal, or a subroutine in FORTRAN.

Is it helpful? Add Comment View Comments
 

Ques 51. Explain which of the following declarations will compile and what will be constant - a pointer or the value pointed at: * const char *
* char const *
* char * const

Note: Ask the candidate whether the first declaration is pointing to a string or a single character. Both explanations are correct, but if he says that it?s a single character pointer, ask why a whole string is initialized as char* in C++. If he says this is a string declaration, ask him to declare a pointer to a single character. Competent candidates should not have problems pointing out why const char* can be both a character and a string declaration, incompetent ones will come up with invalid reasons.

Is it helpful? Add Comment View Comments
 

Ques 52. You?re given a simple code for the class Bank Customer. Write the following functions:
* Copy constructor
* = operator overload
* == operator overload
* + operator overload (customers? balances should be added up, as an example of joint account between husband and wife)

Note:Anyone confusing assignment and equality operators should be dismissed from the interview. The applicant might make a mistake of passing by value, not by reference. The candidate might also want to return a pointer, not a new object, from the addition operator. Slightly hint that you?d like the value to be changed outside the function, too, in the first case. Ask him whether the statement customer3 = customer1 + customer2 would work in the second case.

Is it helpful? Add Comment View Comments
 

Ques 53. What problems might the following macro bring to the application?


#define sq(x) x*x

Is it helpful? Add Comment View Comments
 

Ques 54. Anything wrong with this code?


T *p = new T[10];
delete p;


Everything is correct, Only the first element of the array will be deleted?, The entire array will be deleted, but only the first element destructor will be called.

Is it helpful? Add Comment View Comments
 

Ques 55. Anything wrong with this code?
T *p = 0;
delete p;

Yes, the program will crash in an attempt to delete a null pointer.

Is it helpful? Add Comment View Comments
 

Ques 56. How do you decide which integer type to use?


It depends on our requirement. When we are required an integer to be stored in 1 byte (means less than or equal to 255) we use short int, for 2 bytes we use int, for 8 bytes we use long int.

A char is for 1-byte integers, a short is for 2-byte integers, an int is generally a 2-byte or 4-byte integer (though not necessarily), a long is a 4-byte integer, and a long long is a 8-byte integer.

Is it helpful? Add Comment View Comments
 

Ques 57. What does extern mean in a function declaration?

Using extern in a function declaration we can make a function such that it can used outside the file in which it is defined.

An extern variable, function definition, or declaration also makes the described variable or function usable by the succeeding part of the current source file. This declaration does not replace the definition. The declaration is used to describe the variable that is externally defined.

If a declaration for an identifier already exists at file scope, any extern declaration of the same identifier found within a block refers to that same object. If no other declaration for the identifier exists at file scope, the identifier has external linkage.

Is it helpful? Add Comment View Comments
 

Ques 58. What can I safely assume about the initial values of variables which are not explicitly initialized?


It depends on complier which may assign any garbage value to a variable if it is not initialized.

Is it helpful? Add Comment View Comments
 

Ques 59. What is the difference between char a[] = ?string?; and char *p = ?string?;?


In the first case 6 bytes are allocated to the variable a which is fixed, where as in the second case if *p is assigned to some other value the allocate memory can change.

Is it helpful? Add Comment View Comments
 

Ques 60. What?s the auto keyword good for?


Answer1
Not much. It declares an object with automatic storage duration. Which means the object will be destroyed at the end of the objects scope. All variables in functions that are not declared as static and not dynamically allocated have automatic storage duration by default.

For example
int main()
{
int a; //this is the same as writing ?auto int a;?
}

Answer2
Local variables occur within a scope; they are ?local? to a function. They are often called automatic variables because they automatically come into being when the scope is entered and automatically go away when the scope closes. The keyword auto makes this explicit, but local variables default to auto auto auto auto so it is never necessary to declare something as an auto auto auto auto.

Is it helpful? Add Comment View Comments
 

Ques 61. What is the difference between char a[] = ?string?; and char *p = ?string?; ?


Answer1
a[] = ?string?;
char *p = ?string?;

The difference is this:
p is pointing to a constant string, you can never safely say
p[3]=?x';
however you can always say a[3]=?x';

char a[]=?string?; - character array initialization.
char *p=?string? ; - non-const pointer to a const-string.( this is permitted only in the case of char pointer in C++ to preserve backward compatibility with C.)

Answer2
a[] = ?string?;
char *p = ?string?;

a[] will have 7 bytes. However, p is only 4 bytes. P is pointing to an adress is either BSS or the data section (depending on which compiler ? GNU for the former and CC for the latter).

Answer3
char a[] = ?string?;
char *p = ?string?;

for char a[]??.using the array notation 7 bytes of storage in the static memory block are taken up, one for each character and one for the terminating nul character.

But, in the pointer notation char *p????.the same 7 bytes required, plus N bytes to store the pointer variable ?p? (where N depends on the system but is usually a minimum of 2 bytes and can be 4 or more)??

Is it helpful? Add Comment View Comments
 

Ques 62. What does extern mean in a function declaration?


It tells the compiler that a variable or a function exists, even if the compiler hasn?t yet seen it in the file currently being compiled. This variable or function may be defined in another file or further down in the current file.

Is it helpful? Add Comment View Comments
 

Ques 63. How do I initialize a pointer to a function?

This is the way to initialize a pointer to a function
void fun(int a)
{

}

void main()
{
void (*fp)(int);
fp=fun;
fp(1);

}

Is it helpful? Add Comment View Comments
 

Ques 64. How do you link a C++ program to C functions?


By using the extern "C" linkage specification around the C function declarations.

Is it helpful? Add Comment View Comments
 

Ques 65. Explain the scope resolution operator.


It permits a program to reference an identifier in the global scope that has been hidden by another identifier with the same name in the local scope.

Is it helpful? Add Comment View Comments
 

Ques 66. What are the differences between a C++ struct and C++ class?


The default member and base-class access specifier are different.

Is it helpful? Add Comment View Comments
 

Ques 67. How many ways are there to initialize an int with a constant?


Two.
There are two formats for initializers in C++ as shown in the example that follows. The first format uses the traditional C notation. The second format uses constructor notation.
int foo = 123;
int bar (123);

Is it helpful? Add Comment View Comments
 

Ques 68. How does throwing and catching exceptions differ from using setjmp and longjmp?


The throw operation calls the destructors for automatic objects instantiated since entry to the try block.

Is it helpful? Add Comment View Comments
 

Ques 69. What is a default constructor?


Default constructor WITH arguments class B { public: B (int m = 0) : n (m) {} int n; }; int main(int argc, char *argv[]) { B b; return 0; }

Is it helpful? Add Comment View Comments
 

Ques 70. What is a conversion constructor?


A constructor that accepts one argument of a different type.

Is it helpful? Add Comment View Comments
 

Ques 71. What is the difference between a copy constructor and an overloaded assignment operator?


A copy constructor constructs a new object by using the content of the argument object. An overloaded assignment operator assigns the contents of an existing object to another existing object of the same class.

Is it helpful? Add Comment View Comments
 

Ques 72. When should you use multiple inheritance?


There are three acceptable answers: "Never," "Rarely," and "When the problem domain cannot be accurately modeled any other way."

Is it helpful? Add Comment View Comments
 

Ques 73. Explain the ISA and HASA class relationships. How would you implement each in a class design?


A specialized class "is" a specialization of another class and, therefore, has the ISA relationship with the other class. An Employee ISA Person. This relationship is best implemented with inheritance. Employee is derived from Person. A class may have an instance of another class. For example, an employee "has" a salary, therefore the Employee class has the HASA relationship with the Salary class. This relationship is best implemented by embedding an object of the Salary class in the Employee class.

Is it helpful? Add Comment View Comments
 

Ques 74. When is a template a better solution than a base class?


When you are designing a generic class to contain or otherwise manage objects of other types, when the format and behavior of those other types are unimportant to their containment or management, and particularly when those other types are unknown (thus, the generosity) to the designer of the container or manager class.

Is it helpful? Add Comment View Comments
 

Ques 75. What is a mutable member?


One that can be modified by the class even when the object of the class or the member function doing the modification is const.

Is it helpful? Add Comment View Comments
 

Ques 76. What is an explicit constructor?


A conversion constructor declared with the explicit keyword. The compiler does not use an explicit constructor to implement an implied conversion of types. It?s purpose is reserved explicitly for construction.

Is it helpful? Add Comment View Comments
 

Ques 77. What is the Standard Template Library (STL)?

A library of container templates approved by the ANSI committee for inclusion in the standard C++ specification.
A programmer who then launches into a discussion of the generic programming model, iterators, allocators, algorithms, and such, has a higher than average understanding of the new technology that STL brings to C++ programming.

Is it helpful? Add Comment View Comments
 

Ques 78. Describe run-time type identification.


The ability to determine at run time the type of an object by using the typeid operator or the dynamic_cast operator.

Is it helpful? Add Comment View Comments
 

Ques 79. What problem does the namespace feature solve?


Multiple providers of libraries might use common global identifiers causing a name collision when an application tries to link with two or more such libraries. The namespace feature surrounds a library?s external declarations with a unique namespace that eliminates the potential for those collisions.
This solution assumes that two library vendors don?t use the same namespace identifier, of course.

Is it helpful? Add Comment View Comments
 

Ques 80. Are there any new intrinsic (built-in) data types?


Yes. The ANSI committee added the bool intrinsic type and its true and false value keywords.

Is it helpful? Add Comment View Comments
 

Ques 81. Will the following program execute?
void main()
{
void *vptr = (void *) malloc(sizeof(void));
vptr++;
}

Answer1
It will throw an error, as arithmetic operations cannot be performed on void pointers.

Answer2
It will not build as sizeof cannot be applied to void* ( error ?Unknown size? )

Answer3
How can it execute if it won?t even compile? It needs to be int main, not void main. Also, cannot increment a void *.

Answer4
According to gcc compiler it won?t show any error, simply it executes. but in general we can?t do arthematic operation on void, and gives size of void as 1

Answer5
The program compiles in GNU C while giving a warning for ?void main?. The program runs without a crash. sizeof(void) is ?1? hence when vptr++, the address is incremented by 1.

Answer6
Regarding arguments about GCC, be aware that this is a C++ question, not C. So gcc will compile and execute, g++ cannot. g++ complains that the return type cannot be void and the argument of sizeof() cannot be void. It also reports that ISO C++ forbids incrementing a pointer of type ?void*?.

Answer7
in C++
voidp.c: In function `int main()?:
voidp.c:4: error: invalid application of `sizeof? to a void type
voidp.c:4: error: `malloc? undeclared (first use this function)
voidp.c:4: error: (Each undeclared identifier is reported only once for each function it appears in.)
voidp.c:6: error: ISO C++ forbids incrementing a pointer of type `void*?

But in c, it work without problems

void main()
{
char *cptr = 0?2000;
long *lptr = 0?2000;
cptr++;
lptr++;
printf(? %x %x?, cptr, lptr);
}
Will it execute or not?


Answer1
For Q2: As above, won?t compile because main must return int. Also, 0×2000 cannot be implicitly converted to a pointer (I assume you meant 0×2000 and not 0?2000.)

Answer2
Not Excute.
Compile with VC7 results following errors:
error C2440: ?initializing? : cannot convert from ?int? to ?char *?
error C2440: ?initializing? : cannot convert from ?int? to ?long *?


Not Excute if it is C++, but Excute in C.
The printout:
2001 2004

Answer3
In C++
[$]> g++ point.c
point.c: In function `int main()?:
point.c:4: error: invalid conversion from `int? to `char*?
point.c:5: error: invalid conversion from `int? to `long int*?

in C
????????????
[$] etc > gcc point.c
point.c: In function `main?:
point.c:4: warning: initialization makes pointer from integer without a cast
point.c:5: warning: initialization makes pointer from integer without a cast
[$] etc > ./a.exe
2001 2004

Is it helpful? Add Comment View Comments
 

Ques 82. What is the difference between Mutex and Binary semaphore?

semaphore is used to synchronize processes. where as mutex is used to provide synchronization between threads running in the same process. 

Is it helpful? Add Comment View Comments
 

Ques 83. In C++, what is the difference between method overloading and method overriding?


Overloading a method (or function) in C++ is the ability for functions of the same name to be defined as long as these methods have different signatures (different set of parameters). Method overriding is the ability of the inherited class rewriting the virtual method of the base class.

Is it helpful? Add Comment View Comments
 

Ques 84. What methods can be overridden in Java?


In C++ terminology, all public methods in Java are virtual. Therefore, all Java methods can be overwritten in subclasses except those that are declared final, static, and private.

Is it helpful? Add Comment View Comments
 

Ques 85. What are the defining traits of an object-oriented language?


The defining traits of an object-oriented langauge are:
* encapsulation
* inheritance
* polymorphism

Is it helpful? Add Comment View Comments
 

Ques 86. Write a program that ask for user input from 5 to 9 then calculate the average


int main()
{
int MAX=4;
int total =0;
int average=0;
int numb;
cout<<"Please enter your input from 5 to 9";
cin>>numb;
if((numb <5)&&(numb>9))
cout<<"please re type your input";
else
for(i=0;i<=MAX; i++)
{
total = total + numb;
average= total /MAX;
}
cout<<"The average number is"<<average<<endl;

return 0;
}

Is it helpful? Add Comment View Comments
 

Ques 87. Assignment Operator - What is the diffrence between a "assignment operator" and a "copy constructor"?


Answer1.
In assignment operator, you are assigning a value to an existing object. But in copy constructor, you are creating a new object and then assigning a value to that object. For example:
complex c1,c2;
c1=c2; //this is assignment
complex c3=c2; //copy constructor

Answer2.
A copy constructor is used to initialize a newly declared variable from an existing variable. This makes a deep copy like assignment, but it is somewhat simpler:

There is no need to test to see if it is being initialized from itself.
There is no need to clean up (eg, delete) an existing value (there is none).
A reference to itself is not returned.

Is it helpful? Add Comment View Comments
 

Ques 88. RTTI - What is RTTI?


Answer1.
RTTI stands for "Run Time Type Identification". In an inheritance hierarchy, we can find out the exact type of the objet of which it is member. It can be done by using:

1) dynamic id operator
2) typecast operator

Answer2.
RTTI is defined as follows: Run Time Type Information, a facility that allows an object to be queried at runtime to determine its type. One of the fundamental principles of object technology is polymorphism, which is the ability of an object to dynamically change at runtime.

Is it helpful? Add Comment View Comments
 

Ques 89. STL Containers - What are the types of STL containers?


There are 3 types of STL containers:

1. Adaptive containers like queue, stack
2. Associative containers like set, map
3. Sequence containers like vector, deque

Is it helpful? Add Comment View Comments
 

Ques 90. What is the need for a Virtual Destructor ?


Destructors are declared as virtual because if do not declare it as virtual the base class destructor will be called before the derived class destructor and that will lead to memory leak because derived classâ??s objects will not get freed.Destructors are declared virtual so as to bind objects to the methods at runtime so that appropriate destructor is called.

Is it helpful? Add Comment View Comments
 

Ques 91. What is "mutable"?

Answer1.
"mutable" is a C++ keyword. When we declare const, none of its data members can change. When we want one of its members to change, we declare it as mutable.

Answer2.
A "mutable" keyword is useful when we want to force a "logical const" data member to have its value modified. A logical const can happen when we declare a data member as non-const, but we have a const member function attempting to modify that data member. For example:
class Dummy {
public:
bool isValid() const;
private:
mutable int size_ = 0;
mutable bool validStatus_ = FALSE;
// logical const issue resolved
};

bool Dummy::isValid() const
// data members become bitwise const
{
if (size > 10) {
validStatus_ = TRUE; // fine to assign
size = 0; // fine to assign
}
}


Answer2.
"mutable" keyword in C++ is used to specify that the member may be updated or modified even if it is member of constant object. Example:
class Animal {
private:
string name;
string food;
mutable int age;
public:
void set_age(int a);
};

void main() {
const Animal Tiger(â??Fulffyâ??,'antelopeâ??,1);
Tiger.set_age(2);
// the age can be changed since its mutable
}

Is it helpful? Add Comment View Comments
 

Ques 92. Differences of C and C++
Could you write a small program that will compile in C but not in C++ ?


In C, if you can a const variable e.g.
const int i = 2;
you can use this variable in other module as follows
extern const int i;
C compiler will not complain.

But for C++ compiler u must write
extern const int i = 2;
else error would be generated.

Is it helpful? Add Comment View Comments
 

Ques 93. Bitwise Operations - Given inputs X, Y, Z and operations | and & (meaning bitwise OR and AND, respectively), what is output equal to in?


output = (X & Y) | (X & Z) | (Y & Z);

Is it helpful? Add Comment View Comments
 

Ques 94. What is a modifier?


A modifier, also called a modifying function is a member function that changes the value of  at least one data member. In other words, an operation that modifies the state of an object. Modifiers are also known as ?mutators?. Example: The function mod is a modifier in the following code snippet:

class test
{
int x,y;
public:
test()
{
x=0; y=0;
}
void mod()
{
x=10;
y=15;
}
};

Is it helpful? Add Comment View Comments
 

Ques 95. What is an accessor?


An accessor is a class operation that does not modify the state of an object. The accessor functions need to be declared as const operations

Is it helpful? Add Comment View Comments
 

Ques 96. Differentiate between a template class and class template.

Template class: A generic definition or a parameterized class not instantiated until the client provides the needed information. It?s jargon for plain templates. Class template: A class template specifies how individual classes can be constructed much like the way a class specifies how individual objects can be constructed. It?s jargon for plain classes.

Is it helpful? Add Comment View Comments
 

Ques 97. When does a name clash occur?


A name clash occurs when a name is defined in more than one place. For example., two different class libraries could give two different classes the same name. If you try to use many class libraries at the same time, there is a fair chance that you will be unable to compile or link the program because of name clashes.

Is it helpful? Add Comment View Comments
 

Ques 98. Define namespace.


It is a feature in C++ to minimize name collisions in the global name space. This namespace keyword assigns a distinct name to a library that allows other libraries to use the same identifier names without creating any name collisions. Furthermore, the compiler uses the namespace signature for differentiating the definitions.

Is it helpful? Add Comment View Comments
 

Ques 99. What is the use of ?using? declaration. ?


A using declaration makes it possible to use a name from a namespace without the scope operator.

Is it helpful? Add Comment View Comments
 

Ques 100. What is an Iterator class ?


A class that is used to traverse through the objects maintained by a container class. There are five categories of iterators: input iterators, output iterators, forward iterators, bidirectional iterators, random access. An iterator is an entity that gives access to the contents of a container object without violating encapsulation constraints. Access to the contents is granted on a one-at-a-time basis in order. The order can be storage order (as in lists and queues) or some arbitrary order (as in array indices) or according to some ordering relation (as in an ordered binary tree). The iterator is a construct, which provides an interface that, when called, yields either the next element in the container, or some value denoting the fact that there are no more elements to examine. Iterators hide the details of access to and update of the elements of a container class.
The simplest and safest iterators are those that permit read-only access to the contents of a container class.
 

Is it helpful? Add Comment View Comments
 

Ques 101. What is an incomplete type?


Incomplete types refers to pointers in which there is non availability of the implementation of the referenced location or it points to some location whose value is not available for modification.

int *i=0x400 // i points to address 400
*i=0; //set the value of memory location pointed by i.

Incomplete types are otherwise called uninitialized pointers.

Is it helpful? Add Comment View Comments
 

Ques 102. What is a dangling pointer?


A dangling pointer arises when you use the address of an object after
its lifetime is over. This may occur in situations like returning
addresses of the automatic variables from a function or using the
address of the memory block after it is freed. The following
code snippet shows this:

class Sample
{
public:
int *ptr;
Sample(int i)
{
ptr = new int(i);
}

~Sample()
{
delete ptr;
}
void PrintVal()
{
cout << "The value is " << *ptr;
}
};

void SomeFunc(Sample x)
{
cout << "Say i am in someFunc " << endl;
}

int main()
{
Sample s1 = 10;
SomeFunc(s1);
s1.PrintVal();
}

In the above example when PrintVal() function is
called it is called by the pointer that has been freed by the
destructor in SomeFunc.

Is it helpful? Add Comment View Comments
 

Ques 103. Differentiate between the message and method.

Message:
* Objects communicate by sending messages to each other.
* A message is sent to invoke a method.

Method
* Provides response to a message.
* It is an implementation of an operation.

Is it helpful? Add Comment View Comments
 

Ques 104. What is an adaptor class or Wrapper class?


A class that has no functionality of its own. Its member functions hide the use of a third party software component or an object with the non-compatible interface or a non-object-oriented implementation.

Is it helpful? Add Comment View Comments
 

Ques 105. What is a Null object?


It is an object of some class whose purpose is to indicate that a real object of that class does not exist. One common use for a null object is a return value from a member function that is supposed to return an object with some specified properties but cannot find such an object.
 

Is it helpful? Add Comment View Comments
 

Ques 106. What is class invariant?


A class invariant is a condition that defines all valid states for an object. It is a logical condition to ensure the correct working of a class. Class invariants must hold when an object is created, and they must be preserved under all operations of the class. In particular all class invariants are both preconditions and post-conditions for all operations or member functions of the class.

Is it helpful? Add Comment View Comments
 

Ques 107. What do you mean by Stack unwinding?


It is a process during exception handling when the destructor is called for all local objects between the place where the exception was thrown and where it is caught.

Is it helpful? Add Comment View Comments
 

Ques 108. Define precondition and post-condition to a member function.


Precondition: A precondition is a condition that must be true on entry to a member function. A class is used correctly if preconditions are never false. An operation is not responsible for doing anything sensible if its precondition fails to hold. For example, the interface invariants of stack class say nothing about pushing yet another element on a stack that is already full. We say that isful() is a precondition of the push operation. Post-condition: A post-condition is a condition that must be true on exit from a member function if the precondition was valid on entry to that function. A class is implemented correctly if post-conditions are never false. For example, after pushing an element on the stack, we know that isempty() must necessarily hold. This is a post-condition of the push operation.

Is it helpful? Add Comment View Comments
 

Ques 109. What are the conditions that have to be met for a condition to be an invariant of the class?


* The condition should hold at the end of every constructor.
* The condition should hold at the end of every mutator (non-const) operation.

Is it helpful? Add Comment View Comments
 

Ques 110. What are proxy objects?


Objects that stand for other objects are called proxy objects or surrogates.
template <class t="">
class Array2D
{
public:
class Array1D
{
public:
T& operator[] (int index);
const T& operator[] (int index)const;
};

Array1D operator[] (int index);
const Array1D operator[] (int index) const;
};

The following then becomes legal:

Array2D<float>data(10,20);
cout<<data[3][6]; // fine

Here data[3] yields an Array1D object and the operator [] invocation on that object yields the float in position(3,6) of the original two dimensional array. Clients of the Array2D class need not be aware of the presence of the Array1D class. Objects of this latter class stand for one-dimensional array objects that, conceptually, do not exist for clients of Array2D. Such clients program as if they were using real, live, two-dimensional arrays. Each Array1D object stands for a one-dimensional array that is absent from a conceptual model used by the clients of Array2D. In the above example, Array1D is a proxy class. Its instances stand for one-dimensional arrays that, conceptually, do not exist.

Is it helpful? Add Comment View Comments
 

Ques 111. Name some pure object oriented languages.


Smalltalk, Java, Eiffel, Sather.
 

Is it helpful? Add Comment View Comments
 

Ques 112. What is an orthogonal base class?


If two base classes have no overlapping methods or data they are said to be independent of, or orthogonal to each other. Orthogonal in the sense means that two classes operate in different dimensions and do not interfere with each other in any way. The same derived class may inherit such classes with no difficulty.

Is it helpful? Add Comment View Comments
 

Ques 113. What is a node class?

A node class is a class that,
* relies on the base class for services and implementation,
* provides a wider interface to the users than its base class,
* relies primarily on virtual functions in its public interface
* depends on all its direct and indirect base class
* can be understood only in the context of the base class
* can be used as base for further derivation
* can be used to create objects.
A node class is a class that has added new services or functionality beyond the services inherited from its base class.

Is it helpful? Add Comment View Comments
 

Ques 114. What is a container class? What are the types of container classes?


A container class is a class that is used to hold objects in memory or external storage. A container class acts as a generic holder. A container class has a predefined behavior and a well-known interface. A container class is a supporting class whose purpose is to hide the topology used for maintaining the list of objects in memory. When a container class contains a group of mixed objects, the container is called a heterogeneous container; when the container is holding a group of objects that are all the same, the container is called a homogeneous container.

Is it helpful? Add Comment View Comments
 

Ques 115. How do you write a function that can reverse a linked-list?


Answer1:

void reverselist(void)
{
if(head==0)
return;
if(head-<next==0)
return;
if(head-<next==tail)
{
head-<next = 0;
tail-<next = head;
}
else
{
node* pre = head;
node* cur = head-<next;
node* curnext = cur-<next;
head-<next = 0;
cur-<next = head;

for(; curnext!=0; )
{
cur-<next = pre;
pre = cur;
cur = curnext;
curnext = curnext-<next;
}

curnext-<next = cur;
}
}

Answer2:

node* reverselist(node* head)
{
if(0==head || 0==head->next)
//if head->next ==0 should return head instead of 0;
return 0;

{
node* prev = head;
node* curr = head->next;
node* next = curr->next;

for(; next!=0; )
{
curr->next = prev;
prev = curr;
curr = next;
next = next->next;
}
curr->next = prev;

head->next = 0;
head = curr;
}

return head;
}

Is it helpful? Add Comment View Comments
 

Ques 116. What is polymorphism?


Polymorphism is the idea that a base class can be inherited by several classes. A base class pointer can point to its child class and a base class array can store different child class objects.

Is it helpful? Add Comment View Comments
 

Ques 117. How can you tell what shell you are running on UNIX system?

You can do the Echo $RANDOM. It will return a undefined variable if you are from the C-Shell, just a return prompt if you are from the Bourne shell, and a 5 digit random numbers if you are from the Korn shell. You could also do a ps -l and look for the shell with the highest PID.

Is it helpful? Add Comment View Comments
 

Ques 118. What is pure virtual function?


A class is made abstract by declaring one or more of its virtual functions to be pure. A pure virtual function is one with an initializer of = 0 in its declaration
 

Is it helpful? Add Comment View Comments
 

Ques 119. Write a Struct Time where integer m, h, s are its members


struct Time
{
int m;
int h;
int s;
};

Is it helpful? Add Comment View Comments
 

Ques 120. How do you traverse a Btree in Backward in-order?


Process the node in the right subtree
Process the root
Process the node in the left subtree

Is it helpful? Add Comment View Comments
 

Ques 121. What is the two main roles of Operating System?


As a resource manager
As a virtual machine

Is it helpful? Add Comment View Comments
 

Ques 122. In the derived class, which data member of the base class are visible?


In the public and protected sections.

Is it helpful? Add Comment View Comments
 

Ques 123. Could you tell something about the Unix System Kernel?


The kernel is the heart of the UNIX openrating system, it?s reponsible for controlling the computer?s resouces and scheduling user jobs so that each one gets its fair share of resources.

Is it helpful? Add Comment View Comments
 

Ques 124. What are each of the standard files and what are they normally associated with?


They are the standard input file, the standard output file and the standard error file. The first is usually associated with the keyboard, the second and third are usually associated with the terminal screen.

Is it helpful? Add Comment View Comments
 

Ques 125. Detemine the code below, tell me exectly how many times is the operation sum++ performed ?


for ( i = 0; i < 100; i++ )
for ( j = 100; j > 100 - i; j?)
sum++;

(99 * 100)/2 = 4950
The sum++ is performed 4950 times.

Is it helpful? Add Comment View Comments
 

Ques 126. Give 4 examples which belongs application layer in TCP/IP architecture?


FTP, TELNET, HTTP and TFTP

Is it helpful? Add Comment View Comments
 

Ques 127. What?s the meaning of ARP in TCP/IP?


The "ARP" stands for Address Resolution Protocol. The ARP standard defines two basic message types: a request and a response. a request message contains an IP address and requests the corresponding hardware address; a replay contains both the IP address, sent in the request, and the hardware address.

Is it helpful? Add Comment View Comments
 

Ques 128. What is a Makefile?


Makefile is a utility in Unix to help compile large programs. It helps by only compiling the portion of the program that has been changed.
A Makefile is the file and make uses to determine what rules to apply. make is useful for far more than compiling programs.

Is it helpful? Add Comment View Comments
 

Ques 129. What is deadlock?


Deadlock is a situation when two or more processes prevent each other from running. Example: if T1 is holding x and waiting for y to be free and T2 holding y and waiting for x to be free deadlock happens.

Is it helpful? Add Comment View Comments
 

Ques 130. What is semaphore?

Semaphore is a special variable, it has two methods: up and down. Semaphore performs atomic operations, which means ones a semaphore is called it can not be inturrupted.

The internal counter (= #ups - #downs) can never be negative. If you execute the ?down? method when the internal counter is zero, it will block until some other thread calls the ?up? method. Semaphores are use for thread synchronization.

Is it helpful? Add Comment View Comments
 

Ques 131. Is C an object-oriented language?


C is not an object-oriented language, but limited object-oriented programming can be done in C.

Is it helpful? Add Comment View Comments
 

Ques 132. Name some major differences between C++ and Java.


C++ has pointers; Java does not. Java is platform-independent; C++ is not. Java has garbage collection; C++ does not. Java does have pointers. In fact all variables in Java are pointers. The difference is that Java does not allow you to manipulate the addresses of the pointer

Is it helpful? Add Comment View Comments
 

Ques 133. What is the difference between Stack and Queue?


Stack is a Last In First Out (LIFO) data structure.
Queue is a First In First Out (FIFO) data structure

Is it helpful? Add Comment View Comments
 

Ques 134. Write a fucntion that will reverse a string.


char *strrev(char *s)
{
int i = 0, len = strlen(s);
char *str;
if ((str = (char *)malloc(len+1)) == NULL)
/*cannot allocate memory */
err_num = 2;
return (str);
}
while(len)
str[i++]=s[?len];
str[i] = NULL;
return (str);
}

Is it helpful? Add Comment View Comments
 

Ques 135. What is the software Life-Cycle?


The software Life-Cycle are
1) Analysis and specification of the task
2) Design of the algorithms and data structures
3) Implementation (coding)
4) Testing
5) Maintenance and evolution of the system
6) Obsolescence

Is it helpful? Add Comment View Comments
 

Ques 136. What is the difference between a Java application and a Java applet?


The difference between a Java application and a Java applet is that a Java application is a program that can be executed using the Java interpeter, and a JAVA applet can be transfered to different networks and executed by using a web browser (transferable to the WWW).

Is it helpful? Add Comment View Comments
 

Ques 137. Name 7 layers of the OSI Reference Model?


-Application layer
-Presentation layer
-Session layer
-Transport layer
-Network layer
-Data Link layer
-Physical layer

Is it helpful? Add Comment View Comments
 

Ques 138. What are the advantages and disadvantages of B-star trees over Binary trees?


Answer1
B-star trees have better data structure and are faster in search than Binary trees, but it?s harder to write codes for B-start trees.

Answer2
The major difference between B-tree and binary tres is that B-tree is a external data structure and binary tree is a main memory data structure. The computational complexity of binary tree is counted by the number of comparison operations at each node, while the computational complexity of B-tree is determined by the disk I/O, that is, the number of node that will be loaded from disk to main memory. The comparision of the different values in one node is not counted.

Is it helpful? Add Comment View Comments
 

Ques 139. Write the psuedo code for the Depth first Search.


dfs(G, v) //OUTLINE
Mark v as "discovered"
For each vertex w such that edge vw is in G:
If w is undiscovered:
dfs(G, w); that is, explore vw, visit w, explore from there as much as possible, and backtrack from w to v. Otherwise:
"Check" vw without visiting w. Mark v as "finished".

Is it helpful? Add Comment View Comments
 

Ques 140. Describe one simple rehashing policy.


The simplest rehashing policy is linear probing. Suppose a key K hashes to location i. Suppose other key occupies H[i]. The following function is used to generate alternative locations:
rehash(j) = (j + 1) mod h
where j is the location most recently probed. Initially j = i, the hash code for K. Notice that this version of rehash does not depend on K.

Is it helpful? Add Comment View Comments
 

Ques 141. Describe Stacks and name a couple of places where stacks are useful.


A Stack is a linear structure in which insertions and deletions are always made at one end, called the top. This updating policy is called last in, first out (LIFO). It is useful when we need to check some syntex errors, such as missing parentheses.

Is it helpful? Add Comment View Comments
 

Ques 142. Suppose a 3-bit sequence number is used in the selective-reject ARQ, what is the maximum number of frames that could be transmitted at a time?


If a 3-bit sequence number is used, then it could distinguish 8 different frames. Since the number of frames that could be transmitted at a time is no greater half the numner of frames that could be distinguished by the sequence number, so at most 4 frames can be transmitted at a time.

Is it helpful? Add Comment View Comments
 

Most helpful rated by users:

Related differences

Related interview subjects

All interview subjects

ASP .NET interview questions and answers - Total 31 questions
Microsoft .NET interview questions and answers - Total 60 questions
ASP interview questions and answers - Total 82 questions
C# interview questions and answers - Total 41 questions
LINQ interview questions and answers - Total 20 questions
ChatGPT interview questions and answers - Total 20 questions
NLP interview questions and answers - Total 30 questions
OpenCV interview questions and answers - Total 36 questions
Amazon SageMaker interview questions and answers - Total 30 questions
Hugging Face interview questions and answers - Total 30 questions
TensorFlow interview questions and answers - Total 30 questions
Artificial Intelligence (AI) interview questions and answers - Total 47 questions
Machine Learning interview questions and answers - Total 30 questions
Google Cloud AI interview questions and answers - Total 30 questions
IBM Watson interview questions and answers - Total 30 questions
Embedded C interview questions and answers - Total 30 questions
C++ interview questions and answers - Total 142 questions
VBA interview questions and answers - Total 30 questions
COBOL interview questions and answers - Total 50 questions
R Language interview questions and answers - Total 30 questions
Python Coding interview questions and answers - Total 20 questions
Scala interview questions and answers - Total 48 questions
Swift interview questions and answers - Total 49 questions
Golang interview questions and answers - Total 30 questions
CCNA interview questions and answers - Total 40 questions
AWS interview questions and answers - Total 87 questions
Microsoft Azure interview questions and answers - Total 35 questions
Azure Data Factory interview questions and answers - Total 30 questions
OpenStack interview questions and answers - Total 30 questions
ServiceNow interview questions and answers - Total 30 questions
Snowflake interview questions and answers - Total 30 questions
Oracle APEX interview questions and answers - Total 23 questions
PHIPA interview questions and answers - Total 20 questions
FERPA interview questions and answers - Total 20 questions
DPDP interview questions and answers - Total 30 questions
PIPEDA interview questions and answers - Total 20 questions
GDPR interview questions and answers - Total 30 questions
CCPA interview questions and answers - Total 20 questions
HITRUST interview questions and answers - Total 20 questions
LGPD interview questions and answers - Total 20 questions
PDPA interview questions and answers - Total 20 questions
OSHA interview questions and answers - Total 20 questions
HIPPA interview questions and answers - Total 20 questions
Computer Basics interview questions and answers - Total 62 questions
Computer Science interview questions and answers - Total 50 questions
Operating System interview questions and answers - Total 22 questions
MS Word interview questions and answers - Total 50 questions
Tips and Tricks interview questions and answers - Total 30 questions
PoowerPoint interview questions and answers - Total 50 questions
Data Structures interview questions and answers - Total 49 questions
Computer Networking interview questions and answers - Total 65 questions
Microsoft Excel interview questions and answers - Total 37 questions
PyTorch interview questions and answers - Total 25 questions
Data Science interview questions and answers - Total 23 questions
SciPy interview questions and answers - Total 30 questions
Generative AI interview questions and answers - Total 30 questions
NumPy interview questions and answers - Total 30 questions
Python interview questions and answers - Total 106 questions
Python Pandas interview questions and answers - Total 48 questions
Python Matplotlib interview questions and answers - Total 30 questions
Django interview questions and answers - Total 50 questions
Pandas interview questions and answers - Total 30 questions
Deep Learning interview questions and answers - Total 29 questions
PySpark interview questions and answers - Total 30 questions
Flask interview questions and answers - Total 40 questions
Cassandra interview questions and answers - Total 25 questions
Neo4j interview questions and answers - Total 44 questions
MSSQL interview questions and answers - Total 50 questions
OrientDB interview questions and answers - Total 46 questions
Data Warehouse interview questions and answers - Total 20 questions
SQL interview questions and answers - Total 152 questions
IBM DB2 interview questions and answers - Total 40 questions
Elasticsearch interview questions and answers - Total 61 questions
Data Mining interview questions and answers - Total 30 questions
Oracle interview questions and answers - Total 34 questions
MongoDB interview questions and answers - Total 27 questions
AWS DynamoDB interview questions and answers - Total 46 questions
Entity Framework interview questions and answers - Total 46 questions
Redis Cache interview questions and answers - Total 20 questions
MySQL interview questions and answers - Total 108 questions
Data Modeling interview questions and answers - Total 30 questions
MariaDB interview questions and answers - Total 40 questions
DBMS interview questions and answers - Total 73 questions
Apache Hive interview questions and answers - Total 30 questions
PostgreSQL interview questions and answers - Total 30 questions
SSIS interview questions and answers - Total 30 questions
SQL Query interview questions and answers - Total 70 questions
SQLite interview questions and answers - Total 53 questions
Teradata interview questions and answers - Total 20 questions
Power System interview questions and answers - Total 28 questions
Electrical Engineering interview questions and answers - Total 30 questions
Verilog interview questions and answers - Total 30 questions
Software Engineering interview questions and answers - Total 27 questions
MATLAB interview questions and answers - Total 25 questions
Digital Electronics interview questions and answers - Total 38 questions
VLSI interview questions and answers - Total 30 questions
Civil Engineering interview questions and answers - Total 30 questions
Electrical Machines interview questions and answers - Total 29 questions
Data Engineer interview questions and answers - Total 30 questions
Robotics interview questions and answers - Total 28 questions
AutoCAD interview questions and answers - Total 30 questions
OIC interview questions and answers - Total 30 questions
Web API interview questions and answers - Total 31 questions
Dell Boomi interview questions and answers - Total 30 questions
Talend interview questions and answers - Total 34 questions
Salesforce interview questions and answers - Total 57 questions
IBM DataStage interview questions and answers - Total 20 questions
TIBCO interview questions and answers - Total 30 questions
Informatica interview questions and answers - Total 48 questions
Oracle CXUnity interview questions and answers - Total 29 questions
Web Services interview questions and answers - Total 10 questions
Salesforce Lightning interview questions and answers - Total 30 questions
IBM Integration Bus interview questions and answers - Total 30 questions
Power BI interview questions and answers - Total 24 questions
JSP interview questions and answers - Total 49 questions
Java Concurrency interview questions and answers - Total 30 questions
J2EE interview questions and answers - Total 25 questions
JUnit interview questions and answers - Total 24 questions
Java OOPs interview questions and answers - Total 30 questions
Apache Tapestry interview questions and answers - Total 9 questions
JDBC interview questions and answers - Total 27 questions
Java 11 interview questions and answers - Total 24 questions
Java Garbage Collection interview questions and answers - Total 30 questions
Spring Framework interview questions and answers - Total 53 questions
Java Swing interview questions and answers - Total 27 questions
Java Design Patterns interview questions and answers - Total 15 questions
JPA interview questions and answers - Total 41 questions
Hibernate interview questions and answers - Total 52 questions
JMS interview questions and answers - Total 64 questions
JSF interview questions and answers - Total 24 questions
Java 8 interview questions and answers - Total 30 questions
Java 17 interview questions and answers - Total 20 questions
Servlets interview questions and answers - Total 34 questions
Kotlin interview questions and answers - Total 30 questions
EJB interview questions and answers - Total 80 questions
Java Beans interview questions and answers - Total 57 questions
Java Exception Handling interview questions and answers - Total 30 questions
Spring Boot interview questions and answers - Total 50 questions
Java 15 interview questions and answers - Total 16 questions
Core Java interview questions and answers - Total 306 questions
Java Multithreading interview questions and answers - Total 30 questions
Apache Wicket interview questions and answers - Total 26 questions
JBoss interview questions and answers - Total 14 questions
Log4j interview questions and answers - Total 35 questions
Java Mail interview questions and answers - Total 27 questions
Java Applet interview questions and answers - Total 29 questions
Java 21 interview questions and answers - Total 21 questions
Google Gson interview questions and answers - Total 8 questions
Struts interview questions and answers - Total 84 questions
RMI interview questions and answers - Total 31 questions
Java Support interview questions and answers - Total 30 questions
Apache Camel interview questions and answers - Total 20 questions
JAXB interview questions and answers - Total 18 questions
SAP MM interview questions and answers - Total 30 questions
JIRA interview questions and answers - Total 30 questions
SAP ABAP interview questions and answers - Total 24 questions
SCCM interview questions and answers - Total 30 questions
Tally interview questions and answers - Total 30 questions
Pega interview questions and answers - Total 30 questions
ITIL interview questions and answers - Total 25 questions
Finance interview questions and answers - Total 30 questions
Android interview questions and answers - Total 14 questions
Mobile Computing interview questions and answers - Total 20 questions
Xamarin interview questions and answers - Total 31 questions
iOS interview questions and answers - Total 52 questions
Ionic interview questions and answers - Total 32 questions
Statistics interview questions and answers - Total 30 questions
Digital Marketing interview questions and answers - Total 40 questions
Apache Spark interview questions and answers - Total 24 questions
Full-Stack Developer interview questions and answers - Total 60 questions
IIS interview questions and answers - Total 30 questions
System Design interview questions and answers - Total 30 questions
VISA interview questions and answers - Total 30 questions
SEO interview questions and answers - Total 51 questions
Google Analytics interview questions and answers - Total 30 questions
Cloud Computing interview questions and answers - Total 42 questions
BPO interview questions and answers - Total 48 questions
ANT interview questions and answers - Total 10 questions
HR Questions interview questions and answers - Total 49 questions
REST API interview questions and answers - Total 52 questions
Content Writer interview questions and answers - Total 30 questions
SAS interview questions and answers - Total 24 questions
Control System interview questions and answers - Total 28 questions
Agile Methodology interview questions and answers - Total 30 questions
Hadoop interview questions and answers - Total 40 questions
Banking interview questions and answers - Total 20 questions
Checkpoint interview questions and answers - Total 20 questions
Blockchain interview questions and answers - Total 29 questions
Technical Support interview questions and answers - Total 30 questions
Mainframe interview questions and answers - Total 20 questions
Nature interview questions and answers - Total 20 questions
Chemistry interview questions and answers - Total 50 questions
Docker interview questions and answers - Total 30 questions
Sales interview questions and answers - Total 30 questions
Cryptography interview questions and answers - Total 40 questions
RPA interview questions and answers - Total 26 questions
Interview Tips interview questions and answers - Total 30 questions
College Teachers interview questions and answers - Total 30 questions
SDLC interview questions and answers - Total 75 questions
Blue Prism interview questions and answers - Total 20 questions
Memcached interview questions and answers - Total 28 questions
GIT interview questions and answers - Total 30 questions
Business Analyst interview questions and answers - Total 40 questions
Splunk interview questions and answers - Total 30 questions
DevOps interview questions and answers - Total 45 questions
Accounting interview questions and answers - Total 30 questions
SSB interview questions and answers - Total 30 questions
Algorithm interview questions and answers - Total 50 questions
OSPF interview questions and answers - Total 30 questions
Sqoop interview questions and answers - Total 30 questions
JSON interview questions and answers - Total 16 questions
Computer Graphics interview questions and answers - Total 25 questions
IoT interview questions and answers - Total 30 questions
Insurance interview questions and answers - Total 30 questions
Scrum Master interview questions and answers - Total 30 questions
Accounts Payable interview questions and answers - Total 30 questions
XML interview questions and answers - Total 25 questions
GraphQL interview questions and answers - Total 32 questions
Bitcoin interview questions and answers - Total 30 questions
Active Directory interview questions and answers - Total 30 questions
Laravel interview questions and answers - Total 30 questions
Tableau interview questions and answers - Total 20 questions
Adobe AEM interview questions and answers - Total 50 questions
Kubernetes interview questions and answers - Total 30 questions
Microservices interview questions and answers - Total 30 questions
Apache Kafka interview questions and answers - Total 38 questions
Fashion Designer interview questions and answers - Total 20 questions
Desktop Support interview questions and answers - Total 30 questions
IAS interview questions and answers - Total 56 questions
PHP OOPs interview questions and answers - Total 30 questions
OOPs interview questions and answers - Total 30 questions
Dynamic Programming interview questions and answers - Total 30 questions
SharePoint interview questions and answers - Total 28 questions
CICS interview questions and answers - Total 30 questions
Yoga Teachers Training interview questions and answers - Total 30 questions
Nursing interview questions and answers - Total 40 questions
Linked List interview questions and answers - Total 15 questions
Language in C interview questions and answers - Total 80 questions
Behavioral interview questions and answers - Total 29 questions
School Teachers interview questions and answers - Total 25 questions
RxJS interview questions and answers - Total 29 questions
NodeJS interview questions and answers - Total 30 questions
jQuery interview questions and answers - Total 22 questions
Vue.js interview questions and answers - Total 30 questions
ExtJS interview questions and answers - Total 50 questions
Svelte.js interview questions and answers - Total 30 questions
Shell Scripting interview questions and answers - Total 50 questions
Next.js interview questions and answers - Total 30 questions
Knockout JS interview questions and answers - Total 25 questions
TypeScript interview questions and answers - Total 38 questions
PowerShell interview questions and answers - Total 27 questions
Terraform interview questions and answers - Total 30 questions
JCL interview questions and answers - Total 20 questions
JavaScript interview questions and answers - Total 59 questions
Ajax interview questions and answers - Total 58 questions
Express.js interview questions and answers - Total 30 questions
Ansible interview questions and answers - Total 30 questions
ES6 interview questions and answers - Total 30 questions
Electron.js interview questions and answers - Total 24 questions
Cyber Security interview questions and answers - Total 50 questions
PII interview questions and answers - Total 30 questions
Data Protection Act interview questions and answers - Total 20 questions
BGP interview questions and answers - Total 30 questions
Ethical Hacking interview questions and answers - Total 40 questions
Unix interview questions and answers - Total 105 questions
Weblogic interview questions and answers - Total 30 questions
Tomcat interview questions and answers - Total 16 questions
Glassfish interview questions and answers - Total 8 questions
Ubuntu interview questions and answers - Total 30 questions
Linux interview questions and answers - Total 43 questions
Selenium interview questions and answers - Total 40 questions
Kali Linux interview questions and answers - Total 29 questions
Mobile Testing interview questions and answers - Total 30 questions
UiPath interview questions and answers - Total 38 questions
Quality Assurance interview questions and answers - Total 56 questions
API Testing interview questions and answers - Total 30 questions
Appium interview questions and answers - Total 30 questions
ETL Testing interview questions and answers - Total 20 questions
QTP interview questions and answers - Total 44 questions
Cucumber interview questions and answers - Total 30 questions
Postman interview questions and answers - Total 30 questions
TestNG interview questions and answers - Total 38 questions
SDET interview questions and answers - Total 30 questions
HTML interview questions and answers - Total 27 questions
Flutter interview questions and answers - Total 25 questions
React interview questions and answers - Total 40 questions
React Native interview questions and answers - Total 26 questions
CakePHP interview questions and answers - Total 30 questions
Angular 8 interview questions and answers - Total 32 questions
Angular JS interview questions and answers - Total 21 questions
Web Developer interview questions and answers - Total 50 questions
Dojo interview questions and answers - Total 23 questions
Symfony interview questions and answers - Total 30 questions
GWT interview questions and answers - Total 27 questions
CSS interview questions and answers - Total 74 questions
Ruby On Rails interview questions and answers - Total 74 questions
Yii interview questions and answers - Total 30 questions
Angular interview questions and answers - Total 50 questions
PHP interview questions and answers - Total 27 questions
Oracle JET(OJET) interview questions and answers - Total 54 questions
Frontend Developer interview questions and answers - Total 30 questions
Zend Framework interview questions and answers - Total 24 questions
RichFaces interview questions and answers - Total 26 questions
©2024 WithoutBook