[C/C++] 가변 인자 사용하기

int vsprintf_s(
   char *buffer,
   size_t sizeInBytes,
   const char *format,
   va_list argptr
);

// crt_vsprintf_s.c
// This program uses vsprintf_s to write to a buffer.
// The size of the buffer is determined by _vscprintf.

#include <stdlib.h>
#include <stdarg.h>

void test( char * format, ... )
{
   va_list args;
   int len;
   char * buffer;

   va_start( args, format );
   len = _vscprintf( format, args ) // _vscprintf doesn't count
                               + 1; // terminating '\0'
   buffer = malloc( len * sizeof(char) );
   vsprintf_s( buffer, len, format, args );
   puts( buffer );
   free( buffer );
}

int main( void )
{
   test( "%d %c %d", 123, '<', 456 );
   test( "%s", "This is a string" );
}