Java Matrix Programs (add, multiply, transport)

We can implement a matrix using two dimensional array in Java. The element at row and column can be accessed using index “array[i]“.

Since we are using two-dimensional arrays to create a matrix, we can easily perform various operations on its elements.

So, first of all we're going to get the input from the user which is the two matrices:

	import java.util.Scanner;
	public class Matrix {
	public static void main(String[] args) {
	Scanner read=new Scanner (System.in);
	System.out.print("Put the number of line (Matrix M1): ");
	int l1=read.nextInt() ;
	System.out.print("Put the number of columns (Matrix M1): ");
	int c1=read.nextInt() ;
	int m1 [][] = new int [l1][c1] ;
	for (int i =0 ; i<l1 ; i++){
	for (int j =0 ; j<c1 ; j++){
	System.out.print("M1["+i+"]["+j+"]=" ) ;
	m1[i][j]=read.nextInt();
	}
	}
	display(m1,l1,c1);
	System.out.print("Put the number of line (Matrix T) : ");
	int l2=read.nextInt() ;
	System.out.print("Put the number of columns (Matrix T) : ");
	int c2=read.nextInt() ;
	int t [][] = new int [l2][c2];
	for (int i =0 ; i<l2 ; i++){
	for (int j =0 ; j<c2 ; j++){
	System.out.print("M1["+i+"]["+j+"]=" ) ;
	t[i][j]=read.nextInt();
	}
	}
	display (t,l2,c2);
	AddOfTwoMatrix(m1,t,l1,c1,l2,c2);
	multi2Matrix( m1 , t, l1 , c1, l2 , c2);
	}
	}

view raw main.java hosted with ❤ by GitHub

M1 represent the first matrix and T the second one.

l1, l2: number of lines.
c1, c2:number of columns.

Now that we have the content of the two matrices, let's define the methods: display(), AddOfTwoMatrix(), multi2Matrix():

Display:

	static void display (int a[][],int l ,int c) {
	System.out.println("----------------------") ;
	for (int i =0 ; i<l ; i++){
	for (int j =0 ; j<c ; j++){
	System.out.print(" "+a[i][j] ) ;
	}
	System.out.println() ;
	}
	}

view raw display.java hosted with ❤ by GitHub

Adding Two Matrix:

	static void AddOfTwoMatrix (int m1[][],int m2[][] ,int l1 ,int c1 ,int l2 , int c2) {
	if (l1==l2 && c1==c2) {
	System.out.println("Somme : ") ;
	int s[][] =new int [l1][c1];
	for (int i =0 ; i<c1 ; i++){
	for (int j =0 ; j<l1 ; j++){
	s[i][j]=m1[i][j]+m2[i][j] ;
	System.out.print(" "+s[i][j] ) ;
	}
	System.out.println();
	}
	}else System.out.println("The matrix should be a double matrix !");
	}

view raw addingTwoMatrices.java hosted with ❤ by GitHub

Multiplying Two Matrices:

	static void multi2Matrix (int a[][] , int b[][],int l1 , int c1,int l2 , int c2) {
	if (l1!=c2 && l2!=c1) System.out.println("colons & lines are difrrent !!!");else {
	if (l2!=c1) multi2Matrix( b , a, l2 , c2, l1 , c1);
	else {
	int mult [][] = new int [l1][c2] ;
	for (int i =0 ; i<l1 ; i++){
	for (int j =0 ; j<c2 ; j++){
	for (int k =0 ; k<l2 ; k++){
	mult[i][j]+=a[i][k]*b[k][j] ;
	}
	}
	}
	System.out.println("M * T = ") ;
	display(mult,l1,c2);
	}
	}
	}

view raw multiplyMatrices.java hosted with ❤ by GitHub

Transport Two Matrices:

	static void trans(int a[][],int b[][],int l,int c ){
	if (l==c) {
	for (int i =0 ; i<l ; i++){
	for (int j =0 ; j<c ; j++){
	a[i][j]=b[j][i] ;
	}
	}
	}else System.out.println("The matrix should be a double matrix !");
	}

view raw transportMatrices.java hosted with ❤ by GitHub

Input:

Output: