Matrices in java: In the previous article, we have discussed Java Program to Multiply Two Matrices
In this article we are going to see how we can write a program to check if two matrices are equal in JAVA language.
Java Program to Check Whether Two Matrices are Equal or Not
A 3*3 Matrix is having 3 rows and 3 columns where this 3*3 represents the dimension of the matrix. Means there are 3*3 i.e. total 9 elements in a 3*3 Matrix.
Let’s understand it in more simpler way.
| A00 A01 A02 | Matrix A = | A10 A11 A12 | | A20 A21 A22 | 3*3
Matrix A
represents a 3*3 matrix.- ‘
A
‘ represents the matrix element - ‘
Aij
‘ represents the matrix element at it’s matrix position/index. - ‘
i
‘ represents the row index - ‘
j
‘ represents the column index - Means
A00=Aij
wherei=0
andj=0
,A01=aij
wherei=0
andj=1
and like this. - Here we have started
row
value from 0 andcolumn
value from 0.
Let’s see different ways to check if two matrices are equal or not.
Method-1: Java Program to Check Whether Two Matrices are Equal or Not By Static Initialization of Array Elements
Approach:
- Initialize and declare two arrays of size 3×3 with elements.
- Use two for loops to iterate the rows and columns, then compare the elements at same indexes. If any element is different break out of the loop.
- If all the elements are same, then both these are equal, else not .
Program:
public class Matrix { public static void main(String args[]) { // Initializing the 3X3 matrix i.e. 2D array int mat1[][] = {{19,25,32},{40,54,62},{70,20,60}}; int mat2[][] = {{50,15,10},{98,45,78},{23,73,50}}; int row, col ; boolean flag = true; // Printing the matrices using our user-defined function System.out.print("\nMatrix 1"); printMatrix(mat1); System.out.print("\nMatrix 2"); printMatrix(mat2); // Loops to check if two matrices are equal for(row=0;row<3;row++) for(col=0;col<3;col++) { // Checks whether each element is same in both matrices if(mat1[row][col]!=mat2[row][col]) { // Sets flag to false and breaks out of the loop if any element is not same flag = false; break; } } if(flag) System.out.println("\n\nBoth the matrices are equal"); else System.out.println("\n\nBoth the matrices are not equal"); } // method to print the matrix static void printMatrix(int arr[][]) { int row, col; // Loop to print the elements for(row=0;row<3;row++) { // Used for formatting System.out.print("\n"); for(col=0;col<3;col++) { System.out.print(arr[row][col]+" "); } } System.out.print("\n"); } }
Output: Matrix 1 19 25 32 40 54 62 70 20 60 Matrix 2 50 15 10 98 45 78 23 73 50 Both the matrices are not equal
Method-2: Java Program to Check Whether Two Matrices are Equal or Not By Dynamic Initialization of Array Elements
Approach:
- Initialize and declare two arrays of size 3×3.
- Ask the user for input and store them in the arrays using two for loops.
- Use two for loops to iterate the rows and columns, then compare the elements at same indexes. If any element is different break out of the loop.
- If all the elements are same, then both these are equal, else not .
Program:
import java.util.Scanner; public class Matrix{ public static void main(String args[]) { //Scanner class to take input Scanner scan = new Scanner(System.in); // Initializing the 3X3 matrix i.e. 2D array int mat1[][] = new int[3][3]; int mat2[][] = new int[3][3]; boolean flag = true; int row, col ; // Taking matrix1 input System.out.println("\nEnter the first matrix elements"); for(row=0;row<3;row++) for(col=0;col<3;col++) mat1[row][col] = scan.nextInt(); System.out.print("Matrix 1 : "); //calling printMatrix() method to print matrix-1 printMatrix(mat1); // Taking matrix2 input System.out.println("\nEnter the second matrix elements"); for(row=0;row<3;row++) for(col=0;col<3;col++) mat2[row][col] = scan.nextInt(); System.out.print("Matrix 2 : "); //calling printMatrix() method to print matrix-1 printMatrix(mat2); // Loops to check if two matrices are equal for(row=0;row<3;row++) for(col=0;col<3;col++) { // Checks whether each element is same in both matrices if(mat1[row][col]!=mat2[row][col]) { // Sets flag to false and breaks out of the loop if any element is not same flag = false; break; } } if(flag) System.out.println("\n\nBoth the matrices are equal"); else System.out.println("\n\nBoth the matrices are not equal"); } // Method to print the matrix static void printMatrix(int arr[][]) { int row, col; // Loop to print the elements for(row=0;row<3;row++) { // Used for formatting System.out.print("\n"); for(col=0;col<3;col++) { System.out.print(arr[row][col]+" "); } } System.out.print("\n"); } }
Output: CASE-1(Equal) Enter the first matrix elements Matrix 1 : 1 2 3 4 5 6 7 8 9 Enter the second matrix elements Matrix 2 : 1 2 3 4 5 6 7 8 9 Both the matrices are equal CASE-2(Not equal) Enter the first matrix elements Matrix 1 : 1 2 3 4 5 6 7 8 9 Enter the second matrix elements Matrix 2 : 9 8 7 6 5 4 3 2 1 Both the matrices are not equal
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