求一个3x3的整型矩阵对角线元素之和

求一个3x3的整型矩阵对角线元素之和

#include<stdio.h>
int main()
{
	int arr1[3][3] = { 0 };
	int arr2[3][3] = { 0 };
	int i = 0, j = 0;
	for (i = 0; i < 3; i++)
	{
		for (j = 0; j < 3; j++)
		{
			scanf("%d", &arr1[i][j]);
		}
	}
	for (i = 0; i < 3; i++)
	{
		for (j = 0; j < 3; j++)
		{
			arr2[i][j]=arr1[j][i];
		}
	}
	int sum = 0;
	for (i = 0; i < 3; i++)
	{
		for (j = 0; j < 3; j++)
		{
			if (i == j)
				sum = arr1[i][j] + sum;
		}
	}
	for (i = 0; i < 3; i++)
	{
		for (j = 0; j < 3; j++)
		{
			if (i == j)
				sum = arr2[i][j] + sum;
		}
	}
	sum = sum - arr1[1][1];
	printf("%d\n",sum);
	return 0;
}

输出结果：