C语言实现各位数求和函数

#include <stdio.h>

int sum(int i) {
    int res = 0;
    while (i > 0) {
        res += i % 10;
        i /= 10;
    }
    return res;
}

int main() {
    int n, num;
    scanf('%d', &n);
    for (int i = 0; i < n; i++) {
        scanf('%d', &num);
        printf('%d\n', sum(num));
    }
    return 0;
}