Question

The matrix operations that you should include are Addition, Subtraction and Multiplication. The driver can be as simple as asking the user to enter two matrices and then presenting a simple menu that allows the user to select the operation they want to test. Have the menu in a loop so that the user can test any other operation unless they choose to exit the menu. Also, provide the user an option to select two new matrices. Make sure that the result of every operation is printed out after the operation is chosen. The matrices should hold float values.

Create a Java Class called matrix and uses arrays and add appropriate methods for the matrix operations.

Answer 1

Code :

Matrix.java

import java.util.Scanner;

public class Matrix {   //This class stores the matrix and provides functions for various operations

    private int row;    //stores row count of matrix
    private int column; //stores column count of matrix
    private float[][] array;    //stores the elements of matrix

    public Matrix(int row, int column) {    //parameterized constructor
        this.row = row;
        this.column = column;
        array=new float[row][column];   //initialize the array to store elements
    }

    public void fillMatrix() { //this function takes input from user and fills the matrix
        System.out.println("Please enter matrix elements :");
        Scanner sc = new Scanner(System.in);
        for (int i=0;i<this.row;i++)    //loop over every row in matrix
            for (int j=0;j<this.column;j++) {   //loop over every column in matrix
                this.array[i][j] = sc.nextFloat(); //take float value from user
            }
    }

    public void add(Matrix m) { //this function performs addition operation on matrices
        if (m==null || this.row!=m.row || this.column!=m.column) { //check if both matrices are equal or not
            System.out.println("Error: For addition matrices should be of equal size!");
            return;     // return if matrices are not equal
        }
        Matrix result = new Matrix(this.row,this.column);   //initialize the result matrix
        for (int i=0;i<this.row;i++)    //loop over every row
            for (int j=0;j<this.column;j++) {   //loop over every column
                result.array[i][j] = this.array[i][j] + m.array[i][j]; //add respective matrix elements
            }
        System.out.println("Result after addition:");
        result.printMatrix();   // print the result
    }

    public void subtract(Matrix m) { //this function performs subtraction operation on matrices
        if (m==null || this.row!=m.row || this.column!=m.column) { //check if both matrices are equal or not
            System.out.println("Error: For subtraction matrices should be of equal size!");
            return;     // return if matrices are not equal
        }
        Matrix result = new Matrix(this.row,this.column);   //initialize the result matrix
        for (int i=0;i<this.row;i++)    //loop over every row in matrix
            for (int j=0;j<this.column;j++) {   //loop over every column in matrix
                result.array[i][j] = this.array[i][j] - m.array[i][j]; //subtract respective matrix elements
            }
        System.out.println("Result after subtraction:");
        result.printMatrix();   // print the result
    }

    public void multiply(Matrix m) {    //this function performs multiplication operation on matrices
        if (m==null || this.column!=m.row) {    //check matrices size
            System.out.println("Error: For multiplication first matrix column number and second matrix row number should be of equal!");
            return;     //return if it doesn't meet the requirement
        }
        Matrix result = new Matrix(this.row,this.column);   //initialize the result matrix
        for (int i=0;i<this.row;i++)    //loop over every row in matrix
            for (int j=0;j<this.column;j++) {   //loop over every column in matrix
                float sum = 0.0f;       //initialize the sum to 0.0
                for (int k=0;k<this.column;k++)
                    sum = sum + (this.array[i][k]*m.array[k][j]);   //find the product
                result.array[i][j] = sum;   //store the obtained product from loop
            }
        System.out.println("Result after multiplication:");
        result.printMatrix();   // print the result
    }

    public void printMatrix() {     //this function prints the matrix size and elements
        System.out.printf("Matrix size: %d * %d\n",row,column); //print size
        for (int i=0;i<this.row;i++) {      //loop over every row in matrix
            for (int j=0;j<this.column;j++) {    //loop over every column in matrix
                System.out.printf("%f ",this.array[i][j]); //print the element
            }
            System.out.print("\n");
        }
    }
}

1 import java.util.Scanner; 2 3 public class Matrix { //This class stores the matrix and provides functions for various operations 4 5 6 private int row; //stores row count of matrix private int column; //stores column count of matrix private float[][] array: //stores the elements of matrix 7 8 9 @ 10 public Matrix(int row, int column) { //parameterized constructor this.row = row; this.column = column; array=new float[row][column]; //initialize the array to store elements 11 12 13 14 15 16 17 public void fillMatrix() { //this function takes input from user and fills the matrix System.out.println("Please enter matrix elements :"); Scanner sc = new Scanner(System.in); for (int i=0;i<this.row;i++) //loop over every row in matrix for (int j=0; j<this.column; j++) { //loop over every column in matrix this.array[i][j] = sc.nextFloat(); //take float value from user 18 19 20 21 A malang 22 23 24 25 public void add(Matrix m) { //this function performs addition operation on matrices if (m==null || this.row!=m.row || this.column!=m.column) { // check if both matrices are equal or not System.out.println("Error: For addition matrices should be of equal size!"); return; // return if matrices are not equal 26 27 28 }

Matrix result = new Matrix(this.row, this.column); //initialize the result matrix for (int i=0;i<this.row;i++) //loop over every row for (int i=0; j<this.column; j++) { //loop over every column result.array[i][j] = this.array[i][j] + m.array[i][j]; //add respective matrix elements merling 29 30 31 32 33 34 35 36 37 38 39 40 41 System.out.println("Result after addition:"); result.printMatrix(); // print the result merling o public void subtract(Matrix m) { //this function performs subtraction operation on matrices if (m==null || this.row!=m.row || this.column!=m.column) { // check if both matrices are equal or not System.out.println("Error: For subtraction matrices should be of equal size!"); return; // return if matrices are not equal a } 42 43 44 Matrix result = new Matrix(this.row, this.column); //initialize the result matrix for (int i=0;i<this.row;i++) //loop over every row in matrix for (int j=0; j<this.column; j++) { //loop over every column in matrix result.array[i][j] = this.array[i][j] - m.array[i][i]; // subtract respective matrix elements 45 46 47 a } 48 System.out.println("Result after subtraction:"); result.printMatrix(); // print the result A 49 50 51 52 53 54 55 56 public void multiply(Matrix m) { //this function performs multiplication operation on matrices if (m==null || this.column!=m.row) { //check matrices size System.out.println("Error: For multiplication first matrix column number and second matrix row number should be of equal!"); return; //return if it doesn't meet the requirement merlang

57 58 59 60 Matrix result = new Matrix(this.row, this.column); //initialize the result matrix for (int i=0;i<this.row;i++) //loop over every row in matrix for (int j=0; j<this.column; j++) { //loop over every column in matrix float sum= 0.0f; //initialize the sum to 0.0 for (int k=0;k<this.column;k++) sum = sum + (this.array[i][k]*m.array[k][i]); //find the product result.array[i][j] //store the obtained product from loop 61 62 63 = sum; 64 مها 65 System.out.println("Result after multiplication: "); result.printMatrix(); // print the result 66 67 e } 68 69 70 71 D D public void printMatrix() { //this function prints the matrix size and elements System.out.printf("Matrix size: %d * %d\n", row, column); //print size for (int i=0;i<this.row;i++) { //loop over every row in matrix for (int i=0;i<this.column;i++) { //loop over every column in matrix System.out.printf("%f ", this.array[i][j]); //print the element 72 73 74 KT } 75 System.out.print("\n"); 76 e 77 A } 78 } 79

Main.java

import java.util.Scanner;
//This is the driver class
public class Main {
    public static void main(String args[]) {    //Main function
        Scanner sc = new Scanner(System.in);    //for user input
        System.out.println("Please enter first matrix size:"); //input first matrix
        int row = sc.nextInt(); //row
        int col = sc.nextInt(); //column
        if (row<1||col<1) throw new RuntimeException("Invalid operation!"); // row and column can't be less than 1
        Matrix m1 = new Matrix(row,col);    // create first matrix
        m1.fillMatrix();    //fill first matrix
        System.out.println("Please enter second matrix size:"); //input second matrix
        row = sc.nextInt(); //row
        col = sc.nextInt(); //column
        if (row<1||col<1) throw new RuntimeException("Invalid operation!"); // row and column can't be less than 1
        Matrix m2 = new Matrix(row,col);    //create second matrix
        m2.fillMatrix();    //fill second matrix

        int x=1;
        while(x!=0) {
            displayMenu(); //display the operations
            x = sc.nextInt();   //take user input
            switch (x) {
                case 1:
                    m1.add(m2);     //perform addition
                    break;
                case 2:
                    m1.subtract(m2);    //perform subtraction
                    break;
                case 3:
                    m1.multiply(m2);    //perform multiplication
                    break;
                case 4:
                    System.out.println("Please enter first matrix size:"); //input first matrix
                    row = sc.nextInt(); //row
                    col = sc.nextInt(); //column
                    if (row<1||col<1) throw new RuntimeException("Invalid operation!");
                    m1 = new Matrix(row,col);   //create first matrix
                    m1.fillMatrix();    //fill first matrix
                    System.out.println("Please enter second matrix size:"); //input second matrix
                    row = sc.nextInt(); //row
                    col = sc.nextInt(); //column
                    if (row<1||col<1) throw new RuntimeException("Invalid operation!");
                    m2 = new Matrix(row,col);   //create second matrix
                    m2.fillMatrix();    //fill second matrix
                    break;
                case 0:
                    System.out.println("Thank you!");   //exit
                    x=0;
                    break;
            }
        }
    }

    public static void displayMenu() { //this function displays various matrix operations
        System.out.println("---Menu---");
        System.out.println("1. Addition");
        System.out.println("2. Subtraction");
        System.out.println("3. Multiplication");
        System.out.println("4. Create new matrices");
        System.out.println("0. Exit");
        System.out.print("Enter your option : ");
    }
}

1 2 3 4 5 6 7 8 9 import java.util.Scanner; //This is the driver class public class Main { public static void main(String args[]) { //Main function Scanner sc = new Scanner(System.in); //for user input System.out.println("Please enter first matrix size: "); //input first matrix int row = sc.nextInt(); //row int col = sc.nextInt(); //column if (row<1||col<1) throw new RuntimeException("Invalid operation!"); // row and column can't be less than 1 Matrix m1 = new Matrix(row,col); // create first matrix ml.fillMatrix(); //fill first matrix System.out.println("Please enter second matrix size:"); //input second matrix sc.nextInt(); //row col sc.nextInt(); //column if (row<1||col<1) throw new RuntimeException("Invalid operation!"); // row and column can't be less than 1 Matrix m2 = new Matrix(row,col); //create second matrix m2.fillMatrix(); //fill second matrix 10 11 12 13 row = 14 15 16 17 18 19 20 o 21 22 23 int x=1; while(x!=0) { displayMenu(); //display the operations X = sc.nextInt(); //take user input switch (x) { case 1: m1.add(m2); //perform addition break; case 2: ml.subtract(m2); //perform subtraction 24 25 26 27 28

29 30 31 32 33 34 35 row = 36 37 break; case 3: m1.multiply(m2); //perform multiplication break; case 4: System.out.println("Please enter first matrix size: "); //input first matrix sc.nextInt(); //row col = sc.nextInt(); //column if (row<1||col<1) throw new RuntimeException("Invalid operation!"); ml = new Matrix(row,col); //create first matrix ml.fillMatrix(); //fill first matrix System.out.println("Please enter second matrix size:"); //input second matrix row = sc.nextInt(); //row col = sc.nextInt(); //column if (row<1||col<1) throw new RuntimeException ("Invalid operation!"); m2 = new Matrix(row,col); //create second matrix m2.fillMatrix(); //fill second matrix break; 38 39 48 41 42 43 44 45 46 47 case 0: 48 //exit 49 System.out.println("Thank you!"); x=0; break; 50 51 e } 52 A } 53 } 54

55 56 57 58 public static void displayMenu() { //this function displays various matrix bperations System.out.println("-- ---Menu---"); System.out.println("1. Addition"); System.out.println("2. Subtraction"); System.out.println("3. Multiplication"); System.out.println("4. Create new matrices"); System.out.println("0. Exit"); System.out.print("Enter your option : "); 59 60 61 62 63 } 64 martin

Output:

Please enter first matrix size: 33 Please enter matrix elements : 1.9 2.9 3.8 4.8 5.9 6.0 2.9 3.6 1.8 Please enter second matrix size: 33 Please enter matrix elements : -1.9 2.9 1.9 3.0 -2.0-2.0 -3.9 1.9 5.8 ---Menu--- 1. Addition 2. Subtraction 3. Multiplication 4. Create new matrices 0. Exit Enter your option : 1 Result after addition: Matrix size: 3 * 3 0.000000 4.000000 4.000000 7.000000 3.000000 4.000000 -1.000000 4.000000 6.000000 ---Menu--- 1. Addition 2. Subtraction 3. Multiplication 4. Create new matrices 0. Exit Enter your option : 3

Result after multiplication: Matrix size: 3 * 3 -4.000000 1.000000 12.000000 -7.000000 4.000000 24.000000 4.000000 -1.000000 1.000000 ---Menu--- 1. Addition 2. Subtraction 3. Multiplication 4. Create new matrices 0. Exit Enter your option : 4 Please enter first matrix size: 22 Please enter matrix elements : 1.8 2.8 3.0 4.0 Please enter second matrix size: 22 Please enter matrix elements : 2.9 3.0 4.9 5.0 ---Menu--- 1. Addition 2. Subtraction 3. Multiplication 4. Create new matrices 0. Exit Enter your option : 2

Result after subtraction: Matrix size: 2 * 2 -1.000000 -1.000000 -1.000000 -1.000000 ---Menu--- 1. Addition 2. Subtraction 3. Multiplication 4. Create new matrices 0. Exit Enter your option: Thank you!