to Multiply Two Matrices [Matrix Multiplication]

Write a Program in Java to input two 2-D arrays and perform Matrix Multiplication:

Illustration:

import java.util.*;

class MatrixMultiplication

{

    void printMatrix(int P[][], int r, int c) // Funtion for printing an array

    {

        for(int i=0; i<r; i++)

        {

            for(int j=0; j<c; j++)

            {

                System.out.print(P[i][j]+"\t");

            }

            System.out.println();

        }

    }

     

    public static void main(String args[])throws Exception

    {

        MatrixMultiplication ob = new MatrixMultiplication();

        Scanner sc = new Scanner(System.in);

         

        System.out.print("Enter no. of rows of 1st Matrix : ");

        int r1=sc.nextInt();

        System.out.print("Enter no. of columns of 1st Matrix : ");

        int c1=sc.nextInt();

         

        System.out.print("Enter no. of rows of 2nd Matrix : ");

        int r2=sc.nextInt();

        System.out.print("Enter no. of columns of 2nd Matrix : ");

        int c2=sc.nextInt();

         

        if(c1 != r2) // Condition for Multiplication to be possible

        {

            System.out.println("Matrix Multiplication of the given order is not possible");

        }

        else

        {

            int A[][]=new int[r1][c1]; // Array to store 1st Matrix

            int B[][]=new int[r2][c2]; // Array to store 2nd Matrix

            int C[][]=new int[r1][c2]; // Array to store Result of Multiplication of 2 Matrices

             

            System.out.println("*************************");

            System.out.println("Inputting the 1st Matrix");

            System.out.println("*************************");

            for(int i=0; i<r1; i++)

            {

                for(int j=0; j<c1; j++)

                {

                    System.out.print("Enter an element : ");

                    A[i][j]=sc.nextInt();

                }

            }

            System.out.println("*************************");

            System.out.println("Inputting the 2nd Matrix");

            System.out.println("*************************");

            for(int i=0; i<r2; i++)

            {

                for(int j=0; j<c2; j++)

                {

                    System.out.print("Enter an element : ");

                    B[i][j]=sc.nextInt();

                }

            }

             

            /* Matrix Multiplication Starts Here */

             

            int sum = 0;

            for(int i=0; i<r1; i++)

            {

                for(int j=0; j<c2; j++)

                {

                    for(int k=0; k<c1; k++)

                    {

                        sum = sum + A[i][k]*B[k][j];

                    }

                    C[i][j]=sum;

                    sum=0;

                }

            }

             

            /* Printing all the Matrices */

            System.out.println("n*************************");

            System.out.println("          Output         ");

            System.out.println("*************************");

            System.out.println("The 1st Matrix is");

            ob.printMatrix(A,r1,c1);

            System.out.println("*************************");

            System.out.println("The 2nd Matrix is");

            ob.printMatrix(B,r2,c2);

            System.out.println("************************************");

            System.out.println("The Result of Multiplication is");

            ob.printMatrix(C,r1,c2);

        }

    }

}







Output:

Enter no. of rows of 1st Matrix : 2
Enter no. of columns of 1st Matrix : 3
Enter no. of rows of 2nd Matrix : 3
Enter no. of columns of 2nd Matrix : 2
*************************
Inputting the 1st Matrix
*************************
Enter an element : 8
Enter an element : 1
Enter an element : 2
Enter an element : -5
Enter an element : 6
Enter an element : 7
*************************
Inputting the 2nd Matrix
*************************
Enter an element : -5
Enter an element : 1
Enter an element : 0
Enter an element : 2
Enter an element : -11
Enter an element : 7

*************************
Output
*************************
The 1st Matrix is
8 1 2
-5 6 7
*************************
The 2nd Matrix is
-5 1
0 2
-11 7
************************************
The Result of Multiplication is
-62 24
-52 56