#include <stdarg.h>
//the list of arguments does not know its length:
//the count comes first
double getAvg(int count, ...) {
if (count == 0) {
return 0;
}
va_list args;
va_start(args, count);
double sum = 0;
for (int i = 0; i < count; i++) {
sum += va_arg(args, double);
}
va_end(args);
return sum / count;
}
//the types are not checked: 1.0, not 1
double avg = getAvg(4, 1.0, 2.0, 3.0, 4.0);
//avg is 2.5
printf("avg is %g\n", avg);