C++计算正方形矩阵对角线和

C++计算正方形矩阵对角线和，对角线分为：主对角线（Principal Diagonal）和 次对角线（secondary diagonal）

输入

4

1 2 3 4

4 3 2 1

7 8 9 6

6 5 4 3

输出

Principal Diagonal Sum: 16

Secondary Diagonal Sum: 20

#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
	cin>>n;
	int arr[n+5][n+5];
	for(int i=0;i<n;i++){
		for(int j=0;j<n;j++){
			cin>>arr[i][j];
		}
	}
	int sum1=0,sum2=0;
	for(int i=0;i<n;i++){
		sum1+=arr[i][i];
		sum2+=arr[i][n-1-i];
	}
	cout<<"Principal Diagonal Sum: "<<sum1<<"\n";
	cout<<"Secondary Diagonal Sum: "<<sum2;
	return 0;
}