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

• Last Updated : 17 Mar, 2021

For a given 4 x 4 matrix, the task is to interchange the elements of the first and last columns and then return the resultant matrix.

Examples :

```Input 1 :   1  1  5  0
2  3  7  2
8  9  1  3
6  7  8  2

Output 1 :  0  1  5  1
2  3  7  2
3  9  1  8
2  7  8  6

Input 2 :   7   8  9  10
11  13  14  1
15   7  12 22
11  21  30  1

Output 2 : 10  8   9   7
1  13  14  11
22  7  12  15
1  21  30  11```

Approach:

To get the required output, we need to swap the elements of the first and last column of the stated matrix.

Example

## Java

 `// Java Program to Interchange Elements of the``// First and Last Column in a Matrix`` ` `// Importing input output classes``import` `java.io.*;`` ` `class` `GFG {`` ` `    ``// Declare static variable and initialize to``    ``// order of the matrix``    ``static` `int` `N = ``3``;`` ` `    ``// Method 1``    ``// To swap first and last column in a matrix``    ``static` `void` `Swap_First_Last(``int` `mat[][])``    ``{``        ``int` `cls = N;`` ` `        ``// Interchanging of elements between the``        ``// first and last columns``        ``for` `(``int` `j = ``0``; j < N; j++) {``            ``int` `temp = mat[j][``0``];``            ``mat[j][``0``] = mat[j][N - ``1``];``            ``mat[j][N - ``1``] = temp;``        ``}``    ``}`` ` `    ``// Method 2``    ``// Main driver method``    ``public` `static` `void` `main(String[] args)``    ``{``        ``// Creating 2D integer element matrix``        ``// Custom input matrix``        ``int` `mat[][]``            ``= { { ``1``, ``2``, ``3` `}, { ``4``, ``5``, ``6` `}, { ``7``, ``8``, ``9` `} };`` ` `        ``// Outer loop for rows``        ``for` `(``int` `j = ``0``; j < N; j++) {`` ` `            ``// Inner loop for columns``            ``for` `(``int` `k = ``0``; k < N; k++) {`` ` `                ``// Print the input matrix``                ``System.out.print(mat[j][k] + ``" "``);``            ``}``            ``// Operations over a row is computed so new line``            ``System.out.println();``        ``}`` ` `        ``System.out.println(``"Swapped Matrix as follows : "``);`` ` `        ``// Now, calling the (Method1) to interchange``        ``// first and last columns in above matrix``        ``Swap_First_Last(mat);`` ` `        ``// Now simply print the updated matrix``        ``// Swapped matrix using nested for loops`` ` `        ``// Outer loop for rows``        ``for` `(``int` `j = ``0``; j < N; j++) {`` ` `            ``// Inner loop for columns``            ``for` `(``int` `k = ``0``; k < N; k++)`` ` `                ``// Print the swapped matrix``                ``System.out.print(mat[j][k] + ``" "``);`` ` `            ``// Operations over a row is computed so new line``            ``System.out.println();``        ``}``    ``}``}`
Output
```1 2 3
4 5 6
7 8 9
Swapped Matrix as follows :
3 2 1
6 5 4
9 8 7
```

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