Java Program to Decrement the Matrix Elements by One

In the previous article, we have seen Java Program to Find Unique Elements in a Matrix

In this article we are going to see how we can write a program to decrement each element of the matrix by 1 in JAVA language.

Java Program to Decrement the Matrix Elements by One

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=0, A01=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 Decrement the Matrix Elements by One.

By Static Initialization of Array Elements
By Dynamic Initialization of Array Elements

Method-1: Java Program to Decrement the Matrix Elements by One By Static Initialization of Array Elements

Approach:

Declare and Initialize an array of 3*3 means main matrix is ready.
Declare another resultant array of 3*3 means resultant matrix.
Now take two for loops and iterate each element of the main matrix and decrement each element by one.
Go on storing each decremented element to the resultant matrix.
Print the resultant matrix.

Program:

public class Matrix
{
    public static void main(String args[])
    {

        // Initializing the 3X3 matrix i.e. 2D array
        int arr[][] = {{19,25,32},{40,54,62},{70,20,60}};
        //Resultant matrix
        int resArr[][] = new int[3][3];
        int row, col ;

        System.out.print("The matrix is : ");
        printMatrix(arr);

        // Loops to decrement each element of matrix by 1 
        for(row=0;row<3;row++)
        {
            for(col=0;col<3;col++)
            {
                resArr[row][col] = arr[row][col]+1;
            }   
        }
        
        System.out.print("\nThe matrix after decrementing by 1 is : ");
        printMatrix(resArr);
    }

    // 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:

The matrix is : 
19 25 32 
40 54 62 
70 20 60

The matrix after decrementing by 1 is : 
18 24 31
39 53 61 
69 19 59

Method-2: Java Program to Decrement the Matrix Elements by One By Dynamic Initialization of Array Elements

Approach:

Declare an array of 3*3.
Take the input of array elements from the user, so now main matrix is ready.
Declare another resultant array of 3*3 means resultant matrix.
Now take two for loops and iterate each element of the main matrix and increment each element by one.
Go on storing each decremented element to the resultant matrix.
Print the resultant matrix.

Program:

import java.util.*;

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 arr[][] = new int[3][3];
         //Resultant matrix
        int resArr[][] = new int[3][3];
        int row, col ;
        
        // Taking main matrix input
        System.out.println("Enter matrix elements : ");
        for(row=0;row<3;row++)
            for(col=0;col<3;col++)
                arr[row][col] = scan.nextInt();
      

        System.out.print("The matrix is : ");
        printMatrix(arr);

        // Loops to increment each element of matrix by 1 
        for(row=0;row<3;row++)
        {
            for(col=0;col<3;col++)
            {
                resArr[row][col] = arr[row][col]+1;
            }   
        }
        
        System.out.print("\nThe matrix after decrementing by 1 is : ");
        printMatrix(resArr);
    }

    // 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:

Enter matrix elements : 21 41 61 51 71 11 91 81 31
The matrix is : 
21 41 61 
51 71 11 
91 81 31

The matrix after decrementing by 1 is : 
20 40 60
50 70 10
90 80 30

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