轻松搞定：计算数字矩阵主对角线之和的 C++ 实现

```cpp #include <iostream> using namespace std; int main() { int n; cin >> n; int sum = 0; int num; for (int i = 0; i < n; i++) { for (int j = 0; j < n; j++) { cin >> num; if (i == j) { sum += num; } } } cout << sum << endl; return 0; } ``` ######[AI问答 | 107点数解答 | 2025-12-29 12:22:27]