题解 | 求四位数各个数位之和

#include <iostream>
using namespace std;

int main() {
    int n;
    cin >> n;
    
    int b1= n / 1000;
    int b2= (n / 100) % 10;
    int b3 = (n / 10) % 10;
    int b4 = n % 10;

    int sum = b4+b3+b2+b1;

    cout << sum << endl;

    return 0;
}