# 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.

### 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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