# Java Program to Interchange Elements of First and Last in a Matrix Across Columns

In this article, we will understand how to interchange elements of first and last in a matrix across columns. The matrix has a row and column arrangement of its elements. A matrix with m rows and n columns can be called as m × n matrix.

Individual entries in the matrix are called element and can be represented by a[i][j] which suggests that the element a is present in the ith row and jth column.

Below is a demonstration of the same −

Suppose our input is

The matrix is defined as:
4 5 6 7
1 7 3 4
11 12 13 14
23 24 25 50

The desired output would be

The matrix after swapping the elements:
7 5 6 4
4 7 3 1
14 12 13 11
50 24 25 23

## Algorithm

Step 1 - START
Step 2 - Declare an integer matrix namely input_matrix, and an integer value namely matrix_length.
Step 3 - Define the values.
Step 4 - Iterate over each element of the matrix using multiple for-loops and swap the required elements of the matrix using a temporary variable.
Step 5 - Display the result
Step 5 - Stop

## Example 1

Here, we bind all the operations together under the ‘main’ function.

public class MatrixSwap {
static void swap(int input_matrix[][]) {
}
public static void main(String args[]) {
int input_matrix[][] = {
{ 4, 5, 6, 7 },
{ 1, 7, 3, 4 },
{ 11, 12, 13, 14 },
{ 23, 24, 25, 50 }
};
System.out.println("The matrix is defined as: ");
for (int i = 0; i < input_matrix.length; i++) {
for (int j = 0; j < input_matrix.length; j++)
System.out.print(input_matrix[i][j] + " ");
System.out.println();
}
int matrix_length = input_matrix.length;
for (int i = 0; i < input_matrix.length; i++) {
int temp = input_matrix[i];
input_matrix[i] = input_matrix[i][matrix_length - 1];
input_matrix[i][matrix_length - 1] = temp;
}
System.out.println("\nThe matrix after swapping the elements: ");
for (int i = 0; i < matrix_length; i++) {
for (int j = 0; j < input_matrix.length; j++)
System.out.print(input_matrix[i][j] + " ");
System.out.println();
}
}
}

## Output

The matrix is defined as:
4 5 6 7
1 7 3 4
11 12 13 14
23 24 25 50

The matrix after swapping the elements:
7 5 6 4
4 7 3 1
14 12 13 11
50 24 25 23

## Example 2

Here, we encapsulate the operations into functions exhibiting object oriented programming.

public class MatrixSwap {
static void swap(int input_matrix[][]) {
int matrix_length = input_matrix.length;
for (int i = 0; i < input_matrix.length; i++) {
int temp = input_matrix[i];
input_matrix[i] = input_matrix[i][matrix_length - 1];
input_matrix[i][matrix_length - 1] = temp;
}
System.out.println("\nThe matrix after swapping the elements: ");
for (int i = 0; i < matrix_length; i++) {
for (int j = 0; j < input_matrix.length; j++)
System.out.print(input_matrix[i][j] + " ");
System.out.println();
}
}
public static void main(String args[]) {
int input_matrix[][] = {
{ 4, 5, 6, 7 },
{ 1, 7, 3, 4 },
{ 11, 12, 13, 14 },
{ 23, 24, 25, 50 }
};
System.out.println("The matrix is defined as: ");
for (int i = 0; i < input_matrix.length; i++) {
for (int j = 0; j < input_matrix.length; j++)
System.out.print(input_matrix[i][j] + " ");
System.out.println();
}
swap(input_matrix);
}
}

## Output

The matrix is defined as:
4 5 6 7
1 7 3 4
11 12 13 14
23 24 25 50

The matrix after swapping the elements:
7 5 6 4
4 7 3 1
14 12 13 11
50 24 25 23