题解 | 求四位数各个数位之和

#include <bits/stdc++.h>
using namespace std;

int main() {
    string s;
    int sum = 0;
    cin >> s;
    for (int i = 0; i < s.size(); i++) {
        sum += s[i] - '0';
    }
    cout << sum << endl;
    return 0;
}