#include <stdio.h>

int main(void) {
    int readings[] = {10, 11, 12};
    int total = 0;
    size_t count = sizeof readings / sizeof readings[0];
    for (size_t i = 0; i < count; ++i) { total += readings[i]; }
    if (count == 0) { return 1; }
    double mean = (double)total / (double)count;
    printf("total=%d count=%zu mean=%.2f\n", total, count, mean);
    return 0;
}