202401-programming-assignments/【实践课外】10.函数1/6-4 其右上三角（含主对角线）元素之和。.c

int fun(int a[3][3]) {
    int res = 0;

    for (int i = 0; i < 3; i++) {
        for (int j = i; j < 3; j++) {
            res += a[i][j];
        }
    }

    return res;
}