//This is a program for multplying two matrices.
//
class matrix_mul
{
   //this method prints the entries of matrix on monitor
   public static void print_matrix(int[][] M)
   {
     for(int i=0;i<M.length;i=i+1)
     {  System.out.print("| ");
	for(int j=0;j<M[i].length;j=j+1)
	    System.out.print(M[i][j]+" ");
        System.out.println("|");
     }
   }
   // this method assumes that M and N are matrices
   // and that columns of M = rows of N. Oherwise
   // matrix multiplication is not defined.
   public static int[][] multiply(int[][] M, int[][]N)
   {
     int rows = M.length;
     int columns = N[0].length;
     int[][] R = new int[rows][columns];
     for(int r=0; r<rows; r = r+1)
     {
       for(int c=0;c<columns; c=c+1)
       {
	 int product = 0;
	 for(int i=0;i<N.length;i=i+1)
	     product=product + M[r][i]*N[i][c];
	 R[r][c]=product;
       }
     }
    return R;
   }

   public static void main(String args[])
   {
     //The following is also a way to initialize 2-D arrays of small length.
     int[][] M = {{1,0},{2,2},{3,2}}; 
     int[][] N = {{1,2,3},{4,5,6}};
     System.out.println("Matrix M is : ");
     print_matrix(M);
     System.out.println("Matrix N is : ");
     print_matrix(N);
     int[][] R = multiply(M,N);
     System.out.println("Matrix R is : ");
     print_matrix(R);
   }
}