c - How to find out the number of arguments (using variable arguments) if the first argument just indicates and enum value? -

so given list of enum values. function return integer value. takes in enum value , rest followed integer values. supposed total of following integer values if enum type called total , return total.

like this

#include <stdio.h> #include <stdarg.h>  typedef enum rule {     first, total } rule;  int fund(rule rule, int v1, ...){     switch(rule){     case total:         {             int total = v1, value;             if(v1 == -1) return 0;             va_list ap;              va_start(ap, v1);             value = va_arg(ap, int);             while(value != -1){                 total += value;                 value = va_arg(ap, int);             }             va_end(ap);              return total;         }         break;     case first:         return v1;     }     return -1; }  int main(void){     printf("first:%d\n", fund(first, 1, 2, 3, 4, -1));//first:1     printf("total:%d\n", fund(total, 7, 5, 3, 1, -1));//total:16 }