Swap three variables without using temporary variable

04 Nov, 2021
Given three variables, a, b and c, swap them without temporary variable.Example :  
Input  : a = 10, b = 20 and c = 30
Output : a = 30, b = 10 and c = 20
 
Method 1 (Using Arithmetic Operators) The idea is to get sum in one of the two given numbers. The numbers can then be swapped using the sum and subtraction from sum. We have already discussed swapping two variables here. We can extend the same approaches  
C++
Java
Python3
C#
PHP
Javascript
// C++ program to swap three variables// without using temporary variable.#include <iostream>using namespace std; // Assign c's value to a, a's value to b and// b's value to c.void swapThree(int &a, int &b, int &c){    // Store sum of all in a    a = a + b + c;  // (a = 60)     // After this, b has value of a    b = a - (b+c);  // (b = 60 – (20+30) =10)     // After this, c has value of b    c = a - (b+c);  // (c = 60 – (10 + 30) = 20)     // After this, a has value of c    a = a - (b+c);   //(a = 60 – (10 + 20) = 30)} // Driver codeint main(){    int a = 10, b = 20, c = 30;     cout << "Before swapping a = " << a << ", b = "         << b << ", c = " << c << endl;     swapThree(a, b, c);     cout << "After swapping a = " << a << ", b = "         << b << ", c = " << c << endl;     return 0;}
// Java program to swap three variables// without using temporary variable.class GFG{    static int a, b, c;     // Assign c's value to a, a's value    // to b and b's value to c.    static void swapThree()    {                     // Store sum of all in a        // (a = 60)        a = a + b + c;             // After this, b has value of a        // (b = 60 - (20 + 30) = 10)        b = a - (b + c);             // After this, c has value of b        // (c = 60 - (10 + 30) = 20)        c = a - (b + c);             // After this, a has value of c        // (a = 60 - (10 + 20) = 30)        a = a - (b + c);    }     // Driver Code    public static void main(String []args)    {        a = 10; b = 20; c = 30;        System.out.println("Before swapping a = " +                                 a + ", b = " + b +                                     ", c = " + c);                                     // Calling Function        swapThree();         System.out.println("After swapping a = " +                                a + ", b = " + b +                                    ", c = " + c);    }} // This code is contributed by PrinciRaj1992
# python 3 program to swap three variables# without using temporary variable. # Assign c's value to a, a's value to b and# b's value to c.def swapThree(a, b, c):    # Store sum of all in a    a = a + b + c # (a = 60)     # After this, b has value of a    b = a - (b+c) # (b = 60 – (20+30) =10)     # After this, c has value of b    c = a - (b+c) # (c = 60 – (10 + 30) = 20)     # After this, a has value of c    a = a - (b+c) #(a = 60 – (10 + 20) = 30)         print("After swapping a =",a,", b =",b,", c =",c) # Driver codeif __name__ == '__main__':    a = 10    b = 20    c = 30     print("Before swapping a =",a,", b =",b,", c =",c)     swapThree(a, b, c)     # This code is contributed by# Surendra_Gangwar
// C# program to swap three variables// without using temporary variable.using System; class GFG{     // Assign c's value to a, a's value    // to b and b's value to c.    static void swapThree(ref int a,                        ref int b,                        ref int c)    {    // Store sum of all in a    // (a = 60)        a = a + b + c;     // After this, b has value of a    // (b = 60 – (20 + 30) = 10)        b = a - (b + c);     // After this, c has value of b    // (c = 60 – (10 + 30) = 20)        c = a - (b + c);     // After this, a has value of c    // (a = 60 – (10 + 20) = 30)        a = a - (b + c);    }     // Driver Code    static void Main(String []args)    {                 int a = 10, b = 20, c = 30;        Console.WriteLine("Before swapping a = " +                                a + ", b = " + b +                                    ", c = " + c);                                     // Calling Function        swapThree(ref a, ref b,ref c);         Console.Write("After swapping a = " +                           a + ", b = " + b +                               ", c = " + c);    }} // This code is contributed by Sam007.
<?php// PHP program to swap three// variables without using// temporary variable. // Assign c's value to a,// a's value to b and// b's value to c.function swapThree(&$a, &$b, &$c){    // Store sum of all in a    $a = $a + $b + $c; // (a = 60)     // After this, b has value of a    // (b = 60 – (20+30) =10)    $b = $a - ($b + $c);     // After this, c has value of b    // (c = 60 – (10 + 30) = 20)    $c = $a - ($b + $c);     // After this, a has value of c    //(a = 60 – (10 + 20) = 30)    $a = $a - ($b + $c);} // Driver Code$a = 10; $b = 20; $c = 30; echo "Before swapping a = " , $a ,         ", b = ", $b , ", c = " ,                         $c ,"\n"; swapThree($a, $b, $c); echo "After swapping a = ",$a ,                 ", b = ", $b ,           ", c = ", $c , "\n"; // This code is contributed by ajit?>
<script>// javascript program to swap three variables// without using temporary variable. let a, b, c; // Assign c's value to a, a's value// to b and b's value to c.function swapThree(){             // Store sum of all in a    // (a = 60)    a = a + b + c;     // After this, b has value of a    // (b = 60 - (20 + 30) = 10)    b = a - (b + c);     // After this, c has value of b    // (c = 60 - (10 + 30) = 20)    c = a - (b + c);     // After this, a has value of c    // (a = 60 - (10 + 20) = 30)    a = a - (b + c);} // Driver Codea = 10; b = 20; c = 30;document.write("Before swapping a = " +                         a + ", b = " + b +                             ", c = " + c);                     // Calling FunctionswapThree(); document.write("<br>After swapping a = " +                        a + ", b = " + b +                            ", c = " + c); // This code contributed by Princi Singh</script>
Output :  
Before swapping a = 10, b = 20, c = 30
After swapping a = 30, b = 10, c = 20
Time Complexity: O(1)
Auxiliary Space: O(1)
Thanks to Mazhar MIK for suggesting this method.Method 2 (Using Bitwise XOR) The bitwise XOR operator can be used to swap three variables. The idea is similar to method 1. We first store XOR of all numbers in ‘a’. Then we get individual numbers by doing XOR of this with other two numbers. 
C++
Java
Python3
C#
PHP
Javascript
// C++ program to swap three variables// without using temporary variable#include <iostream>using namespace std; // Assign c's value to a, a's value to b and// b's value to c.void swapThree(int &a, int &b, int &c){    // Store XOR of all in a    a = a ^ b ^ c;     // After this, b has value of a    b = a ^ b ^ c;     // After this, c has value of b    c = a ^ b ^ c;     // After this, a has value of c    a = a ^ b ^ c;} // Driver codeint main(){    int a = 10, b = 20, c = 30;     cout << "Before swapping a = " << a << ", b = "         << b << ", c = " << c << endl;     swapThree(a, b, c);     cout << "After swapping a = " << a << ", b = "         << b << ", c = " << c << endl;     return 0;}
// Java program to swap three variables// without using temporary variable.class GFG{    static int a, b, c;     // Assign c's value to a, a's value    // to b and b's value to c.    static void swapThree()    {        // Store XOR of all in a        a = a ^ b ^ c;         // After this, b has value of a        b = a ^ b ^ c;         // After this, c has value of b        c = a ^ b ^ c;         // After this, a has value of c        a = a ^ b ^ c;    }     // Driver Code    public static void main(String[] args)    {        a = 10;        b = 20;        c = 30;        System.out.println("Before swapping a = " + a +                           ", b = " + b + ",c = " + c);         // Calling Function        swapThree();        System.out.println("After swapping a = " + a +                           ", b = " + b + ", c = " + c);    }} // This code is contributed by Rajput-Ji
# Python program to swap three variables# without using temporary variable # Assign c's value to a, a's value to b and# b's value to c.def swapThree(a, b, c) :     # Store XOR of all in a    a[0] = a[0] ^ b[0] ^ c[0]     # After this, b has value of a[0]    b[0] = a[0] ^ b[0] ^ c[0]     # After this, c has value of b    c[0] = a[0] ^ b[0] ^ c[0]     # After this, a[0] has value of c    a[0] = a[0] ^ b[0] ^ c[0] # Driver codea, b, c = [10], [20], [30] print("Before swapping a = ", a[0],    ", b = ", b[0], ", c = ", c[0]) swapThree(a, b, c) print("After swapping a = ", a[0],   ", b = ", b[0], ", c = ", c[0]) # This code is contributed by SHUBHAMSINGH10
// C# program to swap three variables// without using temporary variable.using System; class GFG{         // Assign c's value to a, a's value    // to b and b's value to c.    static void swapThree(ref int a,                          ref int b,                          ref int c)    {    // Store XOR of all in a        a = a ^ b ^ c;     // After this, b has value of a        b = a ^ b ^ c;     // After this, c has value of b        c = a ^ b ^ c;     // After this, a has value of c        a = a ^ b ^ c;    }     // Driver Code    static void Main(String []args)    {             int a = 10, b = 20, c = 30;        Console.WriteLine( "Before swapping a = " +                            a +", b = " + b +                               ",c = " + c);                                               // Calling Function        swapThree(ref a, ref b,ref c);                  Console.Write("After swapping a = " +                       a +", b = " + b +                       ", c = " + c);                            }} // This code is contributed by Sam007.
<?php//PHP program to swap three variables// without using temporary variable // Assign c's value to a, a's value to b and// b's value to c. function swapThree(&$a, &$b, &$c){    // Store XOR of all in a    $a = $a ^ $b ^ $c;     // After this, b has value of a    $b = $a ^ $b ^ $c;     // After this, c has value of b    $c = $a ^ $b ^ $c;     // After this, a has value of c    $a = $a ^ $b ^ $c;} // Driver code     $a = 10; $b = 20; $c = 30;     echo  "Before swapping a = " , $a , ", b = ",         $b , ", c = " , $c ,"\n";     swapThree($a, $b, $c);     echo "After swapping a = ", $a , ", b = ",         $b , ", c = " , $c ,"\n";      #This code is contributed by ajit?>
<script> // javascript program to swap three variables// without using temporary variable. var a, b, c; // Assign c's value to a, a's value// to b and b's value to c.function swapThree(){    // Store XOR of all in a    a = a ^ b ^ c;     // After this, b has value of a    b = a ^ b ^ c;     // After this, c has value of b    c = a ^ b ^ c;     // After this, a has value of c    a = a ^ b ^ c;} // Driver Codea = 10;b = 20;c = 30;document.write("Before swapping a = " + a +                   ", b = " + b + ", c = " + c); // Calling FunctionswapThree();document.write("<br>")document.write("After swapping a = " + a +                   ", b = " + b + ", c = " + c); // This code contributed by Princi Singh </script>
Output:  
Before swapping a = 10, b = 20, c = 30
After swapping a = 30, b = 10, c = 20
Time Complexity: O(1)
Auxiliary Space: O(1)
The method 1 causes overflow for large values of a, b and c, while method 2 doesn’t.This article is contributed by Shubham. If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail your article to review-team@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above. 
Sam007
jit_t
SURENDRA_GANGWAR
SHUBHAMSINGH10
princiraj1992
Rajput-Ji
princi singh
subhammahato348
Bitwise-XOR
Bit Magic
Bit Magic
Writing code in comment?
Please use ide.geeksforgeeks.org,
generate link and share the link here.