Interchange elements of first and last rows in matrix

Algorithm

Step 1 - START
Step 2 - Declare an integer matrix namely matrix and an integer value namely n.
Step 3 - Define the values.
Step 4 - Run one for loop from i=0 to i<n and swap matrix[0][i] with matrix[n-1][i] using a temporary variable.
Step 5 - Display the result
Step 5 - Stop

C++ Code

// C++ code to swap the element of first
// and last row and display the result
#include <iostream>
using namespace std;

#define n 4
void interchange(int m[][n])
{
int rows = n;

// swapping of element between first
// and last rows
for (int i = 0; i < n; i++)
{
int t = m[0][i];
m[0][i] = m[rows - 1][i];
m[rows - 1][i] = t;
}
}


// Driver function
int main()
{
// input in the array
int matrix[n][n] = { { 11, 0, 1, 6 },
{ 4, 7, 6, 5 },
{ 3, 2, 1, 8 },
{ 5, 4, 0, 7 } };


cout<<"The matrix is defined as:"<<endl;
for(int i=0;i<n;i++){
    for(int j=0;j<n;j++){
        cout<<matrix[i][j]<<" ";
    }
    cout<<endl;
}
interchange(matrix);
cout<<endl;
cout<<"The matrix after swapping the elements:"<<endl;
// printing the interchanged matrix
for (int i = 0; i < n; i++)
{
for (int j = 0; j < n; j++)
cout << matrix[i][j] << " ";
cout << endl;
}
}

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Output

The matrix is defined as:
11 0 1 6 
4 7 6 5 
3 2 1 8 
5 4 0 7 

The matrix after swapping the elements:
5 4 0 7 
4 7 6 5 
3 2 1 8 
11 0 1 6 

You can also try this code with Online C++ Compiler

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Java Code

// Java code to swap the element of first
// and last row and display the result
import java.io.*;
 
public class Interchange {
     
    static void interchangeElement(int matrix[][])
    {
        int rows = matrix.length;
         
        // swapping of element between first
        // and last rows
        for (int i = 0; i < matrix[0].length; i++) {
            int t = matrix[0][i];
            matrix[0][i] = matrix[rows-1][i];
            matrix[rows-1][i] = t;
        }
    }
     
    // Driver code
    public static void main(String args[]) throws IOException
    {
        // input in the array
        int matrix[][] = { { 11, 0, 1, 6 },
{ 4, 7, 6, 5 },
{ 3, 2, 1, 8 },
{ 5, 4, 0, 7 } };
        System.out.print("The matrix is defined as:");    
        System.out.println();        
        interchangeElement(matrix);
        System.out.println();
        System.out.print("The matrix after swapping the elements:"); 
        System.out.println();
        // printing the interchanged matrix
        for (int i = 0; i < matrix.length; i++) {
            for (int j = 0; j < matrix[0].length; j++)
                System.out.print(matrix[i][j] + " ");
            System.out.println();
        }
    }
}

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Output

The matrix is defined as:
11 0 1 6 
4 7 6 5 
3 2 1 8 
5 4 0 7 

The matrix after swapping the elements:
5 4 0 7 
4 7 6 5 
3 2 1 8 
11 0 1 6 

You can also try this code with Online C++ Compiler

Run Code

Python Code

# Python code to swap the element
# of first and last row and display
# the result

def interchangeFirstLast(matrix, n, m):
rows = n

# swapping of element between
# first and last rows
for i in range(n):
t = matrix[0][i]
matrix[0][i] = matrix[rows-1][i]
matrix[rows-1][i] = t


# Driver Program
matrix = [[11, 0, 1, 6],
[4, 7, 6, 5],
[3, 2, 1, 8],
[5, 4, 0, 7]]


n = 4
m = 4
print("The matrix is defined as:\n")
for i in range(n):
for j in range(m):
print(matrix[i][j], end = " ")
print("\n")
interchangeFirstLast(matrix, n, m)
print("The matrix after swapping the elements:\n")


# printing the interchanged matrix
for i in range(n):
for j in range(m):
print(matrix[i][j], end = " ")
print("\n")

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Output

The matrix is defined as:
11 0 1 6 

4 7 6 5 

3 2 1 8
 
5 4 0 7 

The matrix after swapping the elements:

5 4 0 7 

4 7 6 5 

3 2 1 8 

11 0 1 6 

PHP Code

<?php
// PHP code to swap the element of first
// and last row and display the result
$n = 4;
 
function interchangElement(&$matrix)
{
        global $n;
        $rows = $n;
          
        // swapping of element between first
        // and last rows
        for ($i = 0; $i < $n; $i++)
        {
            $t = $matrix[0][$i];
            $matrix[0][$i] = $matrix[$rows - 1][$i];
            $matrix[$rows - 1][$i] = $t;
        }
}
  
// Driver function
 
// input in the array
$matrix = array(array(11, 0, 1, 6),
            array(4, 7, 6, 5),
            array( 3, 2, 1, 8),
            array(5, 4, 0, 7));
echo "The matrix is defined as:\n";    
for ($i = 0; $i < $n; $i++)
{
    for ($j = 0; $j < $n; $j++)
        echo $matrix[$i][$j] . " ";
    echo "\n";
}
interchangElement($matrix);
  echo "\n";
echo "The matrix after swapping the elements:\n";  
// printing the interchanged matrix
for ($i = 0; $i < $n; $i++)
{
    for ($j = 0; $j < $n; $j++)
        echo $matrix[$i][$j] . " ";
    echo "\n";
}
?>

You can also try this code with Online PHP Compiler

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Output

The matrix is defined as:
11 0 1 6 
4 7 6 5 
3 2 1 8 
5 4 0 7 

The matrix after swapping the elements:
5 4 0 7 
4 7 6 5 
3 2 1 8 
11 0 1 6 

You can also try this code with Online PHP Compiler

Run Code

Also see,  Rabin Karp Algorithm

Conclusion

This article extensively discussed how to interchange the elements of the first and last row in a matrix.

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