Multiplication of two Matrix

#include <stdio.h>
#include<conio.h>
void main()
{
  int m, n, p, q, i, j, k, sum = 0;
  int a[10][10], b[10][10], mul[10][10];

  printf("Enter the size of first matrix\n");
  scanf("%d%d", &m, &n);
  printf("Enter the elements:-");

  for (  i = 0 ; i < m ; i++ )
    for ( j = 0 ; j < n ; j++ )
      scanf("%d", &a[i][j]);

  printf("Enter the size of second matrix\n");
  scanf("%d%d", &p, &q);

  if ( n != p )
    printf("Matrices  can't be multiplied");
  else
  {
    printf("Enter the elements\n");

    for ( i = 0 ; i < p ; i++ )
      for ( j = 0 ; j < q ; j++ )
        scanf("%d", &b[i][j]);

    for ( i = 0 ; i < m ; i++ )
    {
      for ( j = 0 ; j < q ; j++ )
      {
        for ( k = 0 ; k< p ; k++ )
        {
          sum = sum + a[i][k]*b[k][j];
        }

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

    printf("multiplication of matrices:-\n");

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

      printf("\n");
    }
  }
}