variadic_with_variabe_datatype.c

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

void foo(char *fmt, ...)
{
   va_list ap;
   int d;
   char c, *s;

   va_start(ap, fmt);

   while (*fmt) {
       switch (*(fmt++)) {

       case 's':
           s = va_arg(ap, char *);
           printf("string %s\n", s);
           break;

       case 'd':
           d = va_arg(ap, int);
           printf("int %d\n", d);
           break;

       case 'c':
           /* need a cast here since va_arg only
              takes fully promoted types */
           c = (char) va_arg(ap, int);
           printf("char %c\n", c);
           break;
       }
   }

   va_end(ap);
}


int main(void)
{
    char *s1 = "First";
    char *s2 = "Second";
    int   d = 42;
    char  c = '?';

    foo("sdcs", s1, d, c, s2);

    return EXIT_SUCCESS;
}