Code# 61:C Program To Multiply two Matrices

#include <stdio.h>

int main()
{
  int m, n, p, q, c, d, k, sum = 0;
  int first[10][10], second[10][10], multiply[10][10];

  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");

  for (  c = 0 ; c < m ; c++ )
    for ( d = 0 ; d < n ; d++ )
      scanf("%d", &first[c][d]);

  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");

    for ( c = 0 ; c < p ; c++ )
      for ( d = 0 ; d < q ; d++ )
        scanf("%d", &second[c][d]);

    for ( c = 0 ; c < m ; c++ )
    {
      for ( d = 0 ; d < q ; d++ )
      {
        for ( k = 0 ; k < p ; k++ )
        {
          sum = sum + first[c][k]*second[k][d];
        }

        multiply[c][d] = sum;
        sum = 0;
      }
    }

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

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

      printf("\n");
    }
  }

  return 0;
}
Output:

Enter the number of rows and columns of first matrix
3 3
Enter the elements of first matrix
0 -1 -1
6 2 4
-4 3 7
Enter the rows and columns of second matrix
3 3
Enter the elements of second matrix
-3 5 8
-1 1 0
-4 3 2
Product of entered matrices:-
-3 2 2
-36 44 56
-19 4 -18