Interchange elements of first and last columns in matrix - GeeksforGeeks

19 Apr, 2021
Given a 4 x 4 matrix, the task is to interchange the elements of first and last columns and show the resulting matrix.Examples:  
Input:
8 9 7 6
4 7 6 5
3 2 1 8
9 9 7 7
Output:
6 9 7 8
5 7 6 4
8 2 1 3
7 9 7 9

Input: 
9 7 5 1
2 3 4 1
5 6 6 5
1 2 3 1
Output: 
1 7 5 9
1 3 4 2
5 6 6 5
1 2 3 1
 
The approach is very simple, we can simply swap the elements of first and last column of the matrix in order to get the desired matrix as output.Below is the implementation of the above approach :  
C++
Java
Python 3
C#
PHP
Javascript
// C++ code to swap the element of first// and last column and display the result#include <iostream>using namespace std; #define n 4 void interchangeFirstLast(int m[][n]){    // swapping of element between first    // and last columns    for (int i = 0; i < n; i++) {        int t = m[i][0];        m[i][0] = m[i][n - 1];        m[i][n - 1] = t;    }} // Driver functionint main(){    // input in the array    int m[n][n] = { { 8, 9, 7, 6 },                    { 4, 7, 6, 5 },                    { 3, 2, 1, 8 },                    { 9, 9, 7, 7 } };     interchangeFirstLast(m);     // printing the interchanged matrix    for (int i = 0; i < n; i++) {        for (int j = 0; j < n; j++)            cout << m[i][j] << " ";        cout << endl;    }}
// Java code to swap the element of first// and last column and display the result import java.io.*; class GFG {    static int n = 4; static void interchangeFirstLast(int m[][]){    int cols = n;     // swapping of element between first    // and last columns    for (int i = 0; i < n; i++) {        int t = m[i][0];        m[i][0] = m[i][n - 1];        m[i][n - 1] = t;    }} // Driver function     public static void main (String[] args) {            // input in the array    int m[][] = { { 8, 9, 7, 6 },                    { 4, 7, 6, 5 },                    { 3, 2, 1, 8 },                    { 9, 9, 7, 7 } };     interchangeFirstLast(m);     // printing the interchanged matrix    for (int i = 0; i < n; i++) {        for (int j = 0; j < n; j++)            System.out.print(m[i][j] + " ");            System.out.println();    }    }}// This code is contributed by inder_verma
# Python3 code to swap the element of# first and last column and display# the result   def interchangeFirstLast(mat, n, m):    rows = n           # swapping of element between    # first and last columns    for i in range(n):            t = mat[i][0];            mat[i][0] = mat[i][n-1];            mat[i][n-1] = t;   # Driver Programmat = [[8, 9, 7, 6],       [4, 7, 6, 5],       [3, 2, 1, 8],       [9, 9, 7, 7]]   n = 4m = 4interchangeFirstLast(mat, n, m)   # printing the interchanged matrixfor i in range(n):    for j in range(m):        print(mat[i][j], end = " ")    print("\n")
// C# code to swap the element of first// and last column and display the resultusing System; class GFG{     static int n = 4; static void interchangeFirstLast(int[, ] m){    int cols = n;     // swapping of element between first    // and last columns    for (int i = 0; i < n; i++)    {        int t = m[i, 0];        m[i, 0] = m[i, n - 1];        m[i, n - 1] = t;    }} // Driver Codepublic static void Main (){// input in the arrayint[,] m = { { 8, 9, 7, 6 },                { 4, 7, 6, 5 },                { 3, 2, 1, 8 },                { 9, 9, 7, 7 } }; interchangeFirstLast(m); // printing the interchanged matrixfor (int i = 0; i < n; i++){    for (int j = 0; j < n; j++)        Console.Write(m[i, j] + " ");        Console.WriteLine();}}} // This code is contributed// by Akanksha Rai
<?php// PHP code to swap the element of first// and last column and display the result function interchangeFirstLast($m, $n){    $cols = $n;     // swapping of element between first    // and last columns    for ($i = 0; $i < $n; $i++)    {        $t = $m[$i][0];        $m[$i][0] = $m[$i][$n - 1];        $m[$i][$n - 1] = $t;    }    return $m ;}     // Driver Code // input in the array$m = array( array( 8, 9, 7, 6 ),            array (4, 7, 6, 5 ),            array (3, 2, 1, 8 ),            array (9, 9, 7, 7 )); $n = 4 ;$m = interchangeFirstLast($m,$n); // printing the interchanged matrixfor ($i = 0; $i < $n; $i++){    for ($j = 0; $j < $n; $j++)        echo $m[$i][$j], " ";             echo "\n" ;} // This code is contributed by Ryuga?>
<script> // Javascript code to swap the element of first// and last column and display the resultn = 4 function interchangeFirstLast(m){    // swapping of element between first    // and last columns    for (var i = 0; i < n; i++)    {        var t = m[i][0];        m[i][0] = m[i][n - 1];        m[i][n - 1] = t;    }} // Driver function// input in the arraym = [ [ 8, 9, 7, 6 ],                [ 4, 7, 6, 5 ],                [ 3, 2, 1, 8 ],                [ 9, 9, 7, 7 ] ];interchangeFirstLast(m); // printing the interchanged matrixfor (var i = 0; i < n; i++){    for (var j = 0; j < n; j++)        document.write( m[i][j] + " ");    document.write("<br>");} // This code is contributed by noob2000.</script>
6 9 7 8 
5 7 6 4 
8 2 1 3 
7 9 7 9
 
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