Language%20in%20C%20Interview%20Questions%20and%20Answers
Question: How do I write a function that takes variable number of arguments?
Answer: The following program demonstrates this.#include <stdio.h> #include <stdarg.h> void main( ) { int i = 10 ; float f = 2.5 ; char *str = "Hello!" ; vfpf ( "%d %f %sn", i, f, str ) ; vfpf ( "%s %s", str, "Hi!" ) ; } void vfpf ( char *fmt, ... ) { va_list argptr ; va_start ( argptr, fmt ) ; vfprintf ( stdout, fmt, argptr ) ; va_end ( argptr ) ; } Here, the function vfpf( ) has called vfprintf( ) that take variable argument lists. va_list is an array that holds information required for the macros va_start and va_end. The macros va_start and va_end provide a portable way to access the variable argument lists. va_start would set up a pointer argptr to point to the first of the variable arguments being passed to the function. The macro va_end helps the called function to perform a normal return. |
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