计算整数n阶矩阵的主/副对角线元素之和并输出

#include "stdio.h"
#define N 3

int main(void)
{
int i = 0, j = 0;
int main_sum = 0, sub_sum = 0;
int matrix

= {0};

//输入数组
for (i = 0; i < N; i++)
{
printf("请输入第%d行元素：\n", i+1);
for (j = 0; j < N; j++)
scanf_s("%d", &matrix[i][j]);
}

//计算主对角线元素之和
for (i = 0, j = 0; i < N; i++, j++)
main_sum += matrix[i][j];

//计算副对角线元素之和
for (i = 0, j = N - 1; i < N; i++, j--)
sub_sum += matrix[i][j];

//输出主副对角线元素的和
printf("矩阵主对角线元素之和为：%d\n", main_sum);
printf("矩阵副对角线元素之和为：%d\n", sub_sum);

return 0;
}