Sum of Diagonal of matrix

    #include <stdio.h>

    void main ()

    {

         static int array[10][10];

        int i, j, m, n, a = 0, sum = 0;


        printf("Enetr 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("%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)

            {

                sum = sum + array[i][i];

                a = a + array[i][m - i - 1];

            }

            printf("\nThe sum of the main diagonal elements is = %d\n", sum);

            printf("The sum of the off diagonal elements is   = %d\n", a);

         }

         else

            printf("The given order is not square matrix\n");

     }