编辑代码

#include <iostream>
using namespace std;

int main() {
    const int M = 6;
    int matrix[M][M] = {
        {1, 2, 3, 4, 5, 6},
        {7, 8, 9, 10, 11, 12},
        {13, 14, 15, 16, 17, 18},
        {19, 20, 21, 22, 23, 24},
        {25, 26, 27, 28, 29, 30},
        {31, 32, 33, 34, 35, 36}
    };

    for (int d = 0; d < M; d++) {
        int sum = 0;
        for (int i = 0, j = M - 1 - d; i < M && j >= 0; i++, j--) {
            sum += matrix[i][j];
        }
        cout << "Sum of diagonal starting at (0," << M - 1 - d << "): " << sum << endl;
    }

    return 0;
}