/* Functions with a variable number of arguments. */

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

float average(int num, ...);

main()
{
     float x;

     x = average(10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10);
     printf("\nThe first average is %f.", x);
     x = average(5, 121, 206, 76, 31, 5);
     printf("\nThe second average is %f.", x);
     return(0);
}

float average(int num, ...)
{
     /* Declare a variable of type va_list. */

     va_list arg_ptr;
     int count, total = 0;

     /* Initialize the argument pointer. */

     va_start(arg_ptr, num);

     /* Retrieve each argument in the variable list. */

     for (count = 0; count < num; count++)
         total += va_arg( arg_ptr, int );

     /* Perform clean-up. */

     va_end(arg_ptr);

     /* Divide the total by the number of values to get the */
     /* average. Cast the total to type float so the value */
     /* returned is type float. */

     return ((float)total/num);
}