Write C Program to interchange diagonals of a matrix

#include <stdio.h>
void main ()
{
static int array[10][10];
int i, j, m, n, a;
printf("Enter the order of the matix \n");
scanf("%d %d", &m, &n);
if (m == n)
{
printf("Enter the co-efficients of the matrix\n");
for (i = 0; i < m; ++i)
{
for (j = 0; j < n; ++j)
{
scanf("%dx%d", &array[i][j]);
}
}
printf("The given matrix is \n");
for (i = 0; i < m; ++i)
{
for (j = 0; j < n; ++j)
{
printf(" %d", array[i][j]);
}
printf("\n");
}
for (i = 0; i < m; ++i)
{
a = array[i][i];
array[i][i] = array[i][m - i - 1];
array[i][m - i - 1] = a;
}
printf("The matrix after changing the \n");
printf("main diagonal & secondary diagonal\n");
for (i = 0; i < m; ++i)
{
for (j = 0; j < n; ++j)
{
printf(" %d", array[i][j]);
}
printf("\n");
}
}
else
printf("The given order is not square matrix\n");
}