Golang Interview Questions and Answers
Freshers / Beginner level questions & answers
Ques 1. What is Golang?
Golang, also known as Go, is a statically typed, compiled programming language designed for simplicity and efficiency.
Ques 2. What is the purpose of the 'init' function in Go?
The 'init' function is used to perform one-time initialization tasks, and it is executed automatically before the 'main' function.
Ques 3. What is the difference between slices and arrays in Go?
Arrays have a fixed size, while slices are dynamically sized and more flexible. Slices are built on top of arrays and provide more functionality.
Ques 4. What is the purpose of the 'defer' keyword in Go?
The 'defer' keyword is used to schedule a function call to be run after the surrounding function completes. It is often used for tasks like cleanup operations.
Ques 5. Explain the difference between a pointer and a value in Go.
A pointer is a variable that stores the memory address of another variable. It allows indirect access to the value stored in that memory address. A value is the actual data stored in a variable.
Ques 6. What is the purpose of the 'new' keyword in Go?
The 'new' keyword in Go is used to allocate memory for a new variable or object. It returns a pointer to the newly allocated memory.
Ques 7. How does error handling work in Go?
In Go, errors are values. Functions return an error value to indicate success or failure. It's a common practice to check for errors explicitly, making the code more robust.
Ques 8. What is the purpose of the 'defer' statement in Go?
The 'defer' statement is used to ensure that a function call is performed later in a program's execution, usually for purposes such as cleanup or releasing resources.
Ques 9. Explain the difference between 'map' and 'slice' in Go.
A 'map' in Go is an unordered collection of key-value pairs, while a 'slice' is an ordered sequence of elements. Maps are used for lookups based on keys, while slices are used for ordered data.
Ques 10. What is the difference between a 'slice' and an 'array' in Go?
Arrays have a fixed size defined at compile-time, while slices are dynamic and can change in size during runtime. Slices are built on top of arrays and offer more flexibility.
Ques 11. What is the purpose of the 'range' keyword in Go?
The 'range' keyword is used in for loops to iterate over items in an array, slice, map, channel, or string. It simplifies the code for iterating over elements.
Ques 12. Explain the concept of anonymous functions in Go.
Anonymous functions, also known as function literals, are functions without a name. They can be defined and invoked inline, making them useful for short-lived and one-time-use functions.
Ques 13. What is the 'nil' value in Go, and how is it used?
'nil' is a predeclared identifier in Go representing the zero value for pointers, channels, maps, slices, and functions. It is used to represent the absence of a value or a zero value for certain types.
Intermediate / 1 to 5 years experienced level questions & answers
Ques 14. Explain Goroutines in Go.
Goroutines are lightweight threads managed by the Go runtime. They are used for concurrent programming and are more efficient than traditional threads.
Ques 15. What is the difference between defer and panic in Go?
Defer is used to schedule a function call to be run after the function completes. Panic is used to terminate a function if it encounters an unrecoverable error.
Ques 16. Explain Channels in Go and how they facilitate communication between goroutines.
Channels are a way for goroutines to communicate with each other and synchronize their execution. They provide a means to send and receive data between goroutines.
Ques 17. Explain the purpose of the 'select' statement in Go.
The 'select' statement is used to wait on multiple communication operations, allowing a goroutine to proceed with the first communication that is ready.
Ques 18. How does Go support concurrent programming?
Go supports concurrent programming through goroutines, channels, and the 'go' keyword. Goroutines are lightweight threads that run concurrently, and channels facilitate communication between them.
Ques 19. Explain the concept of interfaces in Go.
Interfaces define a set of methods that a type must implement to be considered as implementing the interface. It allows polymorphism in Go by enabling the use of different types that satisfy the same interface.
Ques 20. What is a closure in Go?
A closure in Go is a function value that references variables from outside its body. It 'closes over' those variables, allowing the function to access them even when it is called outside the scope where they were defined.
Ques 21. Explain the purpose of the 'context' package in Go.
The 'context' package in Go is used for carrying deadlines, cancellations, and other request-scoped values across API boundaries and between processes.
Ques 22. How does Go support testing?
Go has a built-in testing package ('testing') that provides a testing framework. Tests are written in separate files with the '_test.go' suffix, and the 'go test' command is used to run tests.
Ques 23. What is the purpose of the 'sync' package in Go?
The 'sync' package in Go provides a set of primitives for managing synchronization between goroutines. It includes Mutexes, WaitGroups, and other constructs for safe concurrent programming.
Ques 24. Explain the concept of defer chaining in Go.
In Go, multiple 'defer' statements can be stacked or chained together. They are executed in the reverse order of their appearance, meaning the last 'defer' statement is executed first.
Ques 25. How does Go handle race conditions?
Go uses the 'sync' package and the 'mutex' (Mutual Exclusion) concept to handle race conditions. Mutexes ensure that only one goroutine can access a shared resource at a time.
Ques 26. Explain the purpose of the 'sync.WaitGroup' in Go.
The 'sync.WaitGroup' is used to wait for a collection of goroutines to finish executing. It helps coordinate the execution of multiple goroutines and ensures they all complete before proceeding.
Ques 27. What is the difference between the 'make' and 'new' functions in Go?
'make' is used to create slices, maps, and channels, initializing and returning an initialized value. 'new' is used to allocate memory for a new value and returns a pointer to the zeroed value.
Ques 28. Explain the purpose of the 'context.Context' type in Go.
'context.Context' is used for passing deadlines, cancellations, and other request-scoped values across API boundaries and between processes. It helps manage the context of a request or operation.
Ques 29. What is the purpose of the 'panic' and 'recover' functions in Go?
'panic' is used to terminate a function abruptly, and 'recover' is used to regain control of a panicking goroutine. They are often used together for error handling in exceptional cases.
Experienced / Expert level questions & answers
Ques 30. How does Go handle garbage collection?
Go uses a concurrent garbage collector that runs in the background, reclaiming memory that is no longer in use without stopping the execution of the program.
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