MatrixMultiplication.java

 
import java.util.Scanner;
 
public class MatrixMultiplication {
 
       public static void main(String args [ ]) {
        Scanner scanner = new Scanner(System.in);
        
        System.out.print("Enter number of rows in first matrix : ");
        int rowsMatrix1 = scanner.nextInt();
        System.out.print("Enter number of columns in first matrix / rows in matrix2: ");
        int columnsMatrix1RowsMatrix2 = scanner.nextInt();         //variable name used for understanding convenience, because columns in matrix1 = rows in matrix2
        System.out.print("Enter number of columns in second matrix : ");
        int columnsMatrix2 = scanner.nextInt();
        
        int[][] matrix1 = new int[rowsMatrix1][columnsMatrix1RowsMatrix2];
        int[][] matrix2 = new int[columnsMatrix1RowsMatrix2][columnsMatrix2];
        System.out.println("Enter the first matrix in elements :");
        for (int i = 0; i < matrix1.length; i++) {
            for (int j = 0; j < matrix1[0].length; j++) {
                matrix1[i][j] = scanner.nextInt();
            }
        }
        
        System.out.println("Enter the second matrix elements:");
        for (int i = 0; i < matrix2.length; i++) {
            for (int j = 0; j < matrix2[0].length; j++) {
                matrix2[i][j] = scanner.nextInt();
            }
        }
        
        
        //Multiply matrices
        int[][] productMatrix  = new int[rowsMatrix1][columnsMatrix2];
        for (int i = 0; i < rowsMatrix1; i++) {
            for (int j = 0; j < columnsMatrix2; j++) {
                for (int k = 0; k < columnsMatrix1RowsMatrix2; k++) { //columns in matrix1= rows in matrix2
                    productMatrix[i][j] = productMatrix[i][j] + matrix1[i][k] * matrix2[k][j];
                }
            }
        }
 
        
 
                  System.out.println("\nFirst matrix is : ");
                  for (int i = 0; i < rowsMatrix1; i++) {
                        for (int j = 0; j < columnsMatrix1RowsMatrix2; j++) {
                               System.out.print(matrix1[i][j] + " ");
                        }
                        System.out.println();
                  }
 
                  System.out.println("\nSecond matrix is : ");
                  for (int i = 0; i < columnsMatrix1RowsMatrix2; i++) {
                        for (int j = 0; j < columnsMatrix2; j++) {
                               System.out.print(matrix2[i][j] + " ");
                        }
                        System.out.println();
                  }
 
                  
        System.out.println("\nProduct of matrix1 and matrix2 is");
        for (int i = 0; i < rowsMatrix1; i++) {
            for (int j = 0; j < columnsMatrix2; j++) {
                System.out.print(productMatrix[i][j] + " ");
            }
            System.out.println();
        }
       }
 
    }