#include <stdio.h>


int M1[4][2] = { {1,2}, {3,4}, {5,6}, {7,8}};

int M2[2][8] = { {1,2,3,4,5,6,7,8}, {1,2,3,4,5,6,7,8}};

int M3[4][8];


main()
{
  int i,j;

  matrix_multiply(4,2,M1,2,8,M2,M3);
  
  for (i = 0; i < 4; i++) {
    for (j = 0; j < 8; j++) 
      printf("%d ",M3[i][j]);
    printf("\n");
  }

}

matrix_multiply(r1,c1,A,r2,c2,B,C)
     int r1; /* num of rows of first matrix */
     int c1; /* num of columns of first matrix */
     int r2; /* num of rows of second matrix */
     int c2; /* num of columns of second matrix */
     int  A[4][2], B[2][8]; /* first and second matrix */
     int C[4][8]; /* result matrix */
{
  int i,j;

  for (i = 0; i < r1; i++)
    for (j = 0; j < c2; j++)
      C[i][j] = inner_product(i,c1,A,j,r2,B);
}


inner_product(row,num_columns, M, column, num_rows, N)
     int row; /* row of first matrix used in inner product */
     int column; /* column of second matrix used in inner product */
     int num_rows, num_columns; /* num of rows and columns of first and
				   second matrix respectively */
     int M[4][2], N[2][8]; /* first and second matrix */
{

  int sum = 0;
  int i;

  if (num_columns != num_rows) {
    printf("Error! num_columns (%d) != num_rows (%d)\n", num_columns, 
	   num_rows);
    exit(-1);
  }
  else
    for (i = 0; i < num_columns; i++)
      sum += M[row][i] * N[i][column];
  return(sum);
}