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Swapping four variables without temporary variable
  • Difficulty Level : Medium
  • Last Updated : 22 Oct, 2020

Suppose we have four variables a, b, c, d and we want to perform swapping of these variables in the following manner 
a = b, b = c, c = d, d = a 
without using any other fifth or temporary variable 

Solution : 
Step 1. Swap a and b without using any other variable 
a = a + b 
b = a – b 
a = a – b

Step 2. Swap b and c without using any other varibale 
b = b + c 
c = b – c 
b = b – c 

Step 3. Swap c and d without using any other varibale 
c = c + d 
d = c – d 
c = c – d 

Examples: 



Input : a = 1, b = 2, c = 3, d = 4
Output :After swapping 
        a = 2, b = 3, c = 4, d = 1

Input :a = 6, b = 9, c = 10, d = 50
Output : After swapping : a = 9, b = 10, c = 50, d = 6

Prerequisite : Swapping two variables without temporary variable, Swapping three variables without temporary variable 

CPP




// CPP program to swap 4 variables without
// using temporary variable.
#include <bits/stdc++.h>
using namespace std;
 
void swap(int a, int b, int c, int d)
{
    // swapping a and b variables
    a = a + b;
    b = a - b;
    a = a - b;
 
    // swapping b and c variables
    b = b + c;
    c = b - c;
    b = b - c;
 
    // swapping c and d variables
    c = c + d;
    d = c - d;
    c = c - d;
 
    cout << "values after swapping are : " << endl;
    cout << "a = " << a << endl;
    cout << "b = " << b << endl;
    cout << "c = " << c << endl;
    cout << "d = " << d << endl;
}
 
// Driver code
int main()
{
    // initialising variables
    int a = 1;
    int b = 2;
    int c = 3;
    int d = 4;
 
    cout << "Values before swapping are :" << endl;
    cout << "a = " << a << endl;
    cout << "b = " << b << endl;
    cout << "c = " << c << endl;
    cout << "d = " << d << endl << endl;
 
    // Function call
    swap(a, b, c, d);
 
    return 0;
}

Java




// Java program to swap 4 variables
// without using temporary variable.
class GFG {
 
    static void swap(int a, int b, int c, int d)
    {
 
        // swapping a and b variables
        a = a + b;
        b = a - b;
        a = a - b;
 
        // swapping b and c variables
        b = b + c;
        c = b - c;
        b = b - c;
 
        // swapping c and d variables
        c = c + d;
        d = c - d;
        c = c - d;
 
        System.out.println("values after "
                           + "swapping are : ");
        System.out.println("a = " + a);
        System.out.println("b = " + b);
        System.out.println("c = " + c);
        System.out.println("d = " + d);
    }
 
    // Driver code
    public static void main(String[] args)
    {
 
        // initialising variables
        int a = 1;
        int b = 2;
        int c = 3;
        int d = 4;
 
        System.out.println("values before "
                           + "swapping are : ");
        System.out.println("a = " + a);
        System.out.println("b = " + b);
        System.out.println("c = " + c);
        System.out.println("d = " + d);
        System.out.println("");
       
        // Function call
        swap(a, b, c, d);
    }
}
 
// This code is contributed by Smitha.

Python3




# Python 3 program to swap 4 variables
# without using temporary variable.
 
 
def swap(a, b, c, d):
 
    # swapping a and b variables
    a = a + b
    b = a - b
    a = a - b
 
    # swapping b and c variables
    b = b + c
    c = b - c
    b = b - c
 
    # swapping c and d variables
    c = c + d
    d = c - d
    c = c - d
 
    print("values after swapping are : ")
    print("a = ", a)
    print("b = ", b)
    print("c = ", c)
    print("d = ", d)
 
 
# Driver code
 
# initialising variables
a = 1
b = 2
c = 3
d = 4
 
print("values before swapping are : ")
print("a = ", a)
print("b = ", b)
print("c = ", c)
print("d = ", d)
print("")
 
# Function call
swap(a, b, c, d)
 
# This code is contributed by Smitha.

C#




// C# program to swap 4 variables
// without using temporary variable.
using System;
 
class GFG {
 
    static void swap(int a, int b, int c, int d)
    {
        // swapping a and b variables
        a = a + b;
        b = a - b;
        a = a - b;
 
        // swapping b and c variables
        b = b + c;
        c = b - c;
        b = b - c;
 
        // swapping c and d variables
        c = c + d;
        d = c - d;
        c = c - d;
 
        Console.WriteLine("values after "
                          + "swapping are : ");
        Console.WriteLine("a = " + a);
        Console.WriteLine("b = " + b);
        Console.WriteLine("c = " + c);
        Console.WriteLine("d = " + d);
    }
 
    // Driver Code
    public static void Main()
    {
 
        // initialising variables
        int a = 1;
        int b = 2;
        int c = 3;
        int d = 4;
 
        Console.WriteLine("values before "
                          + "swapping are : ");
        Console.WriteLine("a = " + a);
        Console.WriteLine("b = " + b);
        Console.WriteLine("c = " + c);
        Console.WriteLine("d = " + d);
        Console.WriteLine("");
       
        // Function call
        swap(a, b, c, d);
    }
}
 
// This code is contributed by Smitha.

PHP




<?php
// PHP program to swap 4 variables
// without using temporary variable
 
function swap($a, $b, $c, $d)
{
     
    // swapping a and b variables
    $a = $a + $b;
    $b = $a - $b;
    $a = $a - $b;
 
    // swapping b and c variables
    $b = $b + $c;
    $c = $b - $c;
    $b = $b - $c;
 
    // swapping c and d variables
    $c = $c + $d;
    $d = $c - $d;
    $c = $c - $d;
 
    echo "values after swapping are : ","\n";
    echo "a = " , $a ,"\n";
    echo "b = " , $b ,"\n";
    echo "c = " ,$c ,"\n";
    echo "d = " , $d ,"\n";
}
 
    // Driver Code
    // initialising variables
    $a = 1;
    $b = 2;
    $c = 3;
    $d = 4;
 
    echo "Values before swapping are :" ,"\n";
    echo "a = " , $a ,"\n";
    echo "b = " ,$b,"\n";
    echo "c = " , $c ,"\n";
    echo "d = " , $d ,"\n","\n";
 
    // Function call
    swap($a, $b, $c, $d);
 
// This code is contributed by aj_36
?>
Output
Values before swapping are :
a = 1
b = 2
c = 3
d = 4

values after swapping are : 
a = 2
b = 3
c = 4
d = 1

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