Function: find the sum of the elements on the main and sub diagonal of the matrix with 5 rows and 5 columns. Note that the elements where the two diagonals intersect are added only once. For example,

subject ：

Code details ：
 

 

#include <stdio.h>
#define M 5

int fun(int a[M][M])
{

	/**********Program**********/
	int i, j, sum = 0;
	for (i = 0; i < M; i++)
	{
		sum += a[i][i];
		sum += a[i][M - i - 1];
	}
	if (M & 1) sum -= a[M / 2][M / 2];
	return sum;
		/**********  End  **********/
}
int main()
{
	int a[M][M] = { {1,3,5,7,9},{2,4,6,8,10},{2,3,4,5,6},{4,5,6,7,8},{1,3,4,5,6} };
	int y;
	y = fun(a);
	printf("s=%d\n", y);
}