求对角线之和

解题思路:

注意事项:

参考代码:

#include<iostream>

using namespace std;

#define N 100

int main()

{

int n,sum=0;

cin >> n;

int a[N][N];

for (int i = 0; i < n; i++)

for (int j = 0; j < n; j++)

{

cin >> a[i][j];

if (i == j || i + j == n - 1)

sum += a[i][j];

}

cout << sum;

}