Matrix multiplication in c language

Matrix multiplication in c language: c program to multiply matrices (two dimensional array), this program multiplies two matrices which will be entered by the user. Firstly user will enter the order of a matrix. If the entered orders of two matrix is such that they can't be multiplied then an error message is displayed on the screen. You have already studied the logic to multiply them in Mathematics. 

Program:

#include <stdio.h>
int main()
{

  int m, n, p, q, i, j, k, sum = 0;
  int first[10][10], second[10][10], multiply[10][10]; // There are three array

  printf("Enter the number of rows and columns of first matrix\n");
  scanf("%d%d", &m, &n);
  printf("Enter the elements of first matrix\n");

  // take input for first matrix
  for (i = 0; i < m; i++)
  {
    for (j = 0; j < n; j++)
    {
        scanf("%d", &first[i][j]);
    }
  }

  printf("Enter the number of rows and columns of second matrix\n");
  scanf("%d%d", &p, &q);

  if (n != p)
    printf("Matrices with entered orders can't be multiplied with each other.\n");
  else
  {
    printf("Enter the elements of second matrix\n");

    // take input for second matrix
    for (i = 0; i < p; i++)
    {
        for (j = 0; j < q; j++)
        {
            scanf("%d", &second[i][j]);
        }
    }

    // calculation
    for (i = 0; i < m; i++)
    {
      for (j = 0; j < q; j++)
      {
        for (k = 0; k < p; k++)
        {
          sum = sum + first[i][k] * second[k][j];
        }

        multiply[i][j] = sum;
        sum = 0;
      }
    }

    printf("Product of entered matrices:-\n");

    for (i = 0; i < m; i++)
    {
      for (j = 0; j < q; j++)
      {
         printf("%d\t", multiply[i][j]);
      }
      printf("\n");
    }
  }

  return 0;
}

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