# Matrices in java – Java Program to Check Whether Two Matrices are Equal or Not

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  where i=0 and j=0A01=aij where i=0 and j=1 and like this.
• Here we have started row value from 0 and column 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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