Swap Two Variables in One Line
Last Updated :
21 Jun, 2022
We have discussed different approaches to swap two integers without the temporary variable. How to swap into a single line without using the library function?
1) Python: In Python, there is a simple and syntactically neat construct to swap variables, we just need to write "x, y = y, x".
2) C/C++: Below is one generally provided classical solution:
// Swap using bitwise XOR (Wrong Solution in C/C++)
x ^= y ^= x ^= y;
The above solution is wrong in C/C++ as it causes undefined behavior (the compiler is free to behave in any way). The reason is, modifying a variable more than once in an expression causes undefined behavior if there is no sequence point between the modifications.
However, we can use a comma to introduce sequence points. So the modified solution is
// Swap using bitwise XOR (Correct Solution in C/C++)
// sequence point introduced using comma.
(x ^= y), (y ^= x), (x ^= y);
3) Java: In Java, rules for subexpression evaluations are clearly defined. The left-hand operand is always evaluated before the right-hand operand. In Java, the expression "x ^= y ^= x ^= y;" doesn't produce the correct result according to Java rules. It makes x = 0. However, we can use "x = x ^ y ^ (y = x);" Note the expressions are evaluated from left to right. If x = 5 and y = 10 initially, the expression is equivalent to "x = 5 ^ 10 ^ (y = 5);". Note that we can't use this in C/C++ as in C/C++, it is not defined whether the left operand or right operand is executed by any operator (See this for more details).
4) JavaScript: Using destructing assignment, we can simply achieve swapping using this one line.
[x,y]=[y,x]
C
// C program to swap two variables in single line
#include <stdio.h>
int main()
{
int x = 5, y = 10;
(x ^= y), (y ^= x), (x ^= y);
printf("After Swapping values of x and y are %d %d", x,
y);
return 0;
}
C++
// C++ code to swap using XOR
#include <bits/stdc++.h>
using namespace std;
int main()
{
int x = 5, y = 10;
// Code to swap 'x' and 'y'
// to swap two numbers in one
// line
x = x ^ y, y = x ^ y, x = x ^ y;
// printing the swapped variables
cout << "After Swapping: x = "
<< x << ", y= " << y;
return 0;
}
Java
// Java program to swap two variables in a single line
class GFG {
public static void main(String[] args)
{
int x = 5, y = 10;
x = x ^ y ^ (y = x);
System.out.println(
"After Swapping values"
+" of x and y are " + x
+ " " + y);
}
}
Python3
# Python program to swap two variables in a single line
x = 5
y = 10
x, y = y, x
print("After Swapping values of x and y are", x, y)
C#
// C# program to swap two
// variables in single line
using System;
class GFG {
static public void Main()
{
int x = 5, y = 10;
x = x ^ y ^ (y = x);
Console.WriteLine("After Swapping values "
+ "of x and y are " + x + " "
+ y);
}
}
// This code is contributed by aj_36
PHP
<?php
// PHP program to swap two
// variables in single line
// Driver Code
$x = 5;
$y = 10;
($x ^= $y);
($y ^= $x);
($x ^= $y);
echo "After Swapping values of x and y are "
,$x," ", $y;
// This code is contributed by Vishal Tripathi
?>
JavaScript
<script>
// javascript program to swap two variables in single line
let x = 5, y = 10;
(x ^= y), (y ^= x), (x ^= y);
document.write("After Swapping values of x and y are ", x + " ",
y);
// This code is contributed by Surbhi Tyagi
</script>
Output
After Swapping values of x and y are 10 5
Alternate Solutions:
- Using swap(): C++ library function
- b = (a + b) - (a = b);
- a += b - (b = a);
- a = a * b / (b = a)
- a = a ^ b ^ (b = a)
Time complexity : O(1)
Auxiliary Space : O(1)
Similar Reads
Java Program to Swap two Variables Given two numbers x and y, we need to swap their values. In this article, we will learn the Swapping of two numbers in Java.Examples of SwappingInput : x = 10, y = 20;Output : x = 20, y = 10Input : x = 213, y = 109Output : x = 109, y = 213Steps to Swap Two Numbers in JavaBelow are the simple steps w
4 min read
Assigning multiple variables in one line in Python A variable is a segment of memory with a unique name used to hold data that will later be processed. Although each programming language has a different mechanism for declaring variables, the name and the data that will be assigned to each variable are always the same. They are capable of storing val
2 min read
Swap Two Numbers Without Using Third Variable Given two variables a and y, swap two variables without using a third variable. Examples: Input: a = 2, b = 3Output: a = 3, b = 2Input: a = 20, b = 0Output: a = 0, b = 20Input: a = 10, b = 10Output: a = 10, b = 10Table of ContentUsing Arithmetic OperatorsUsing Bitwise XORBuilt-in SwapUsing Arithmeti
6 min read
unordered_multiset swap() in C++ STL The swap() method of âunordered_multisetâ swaps the contents of two containers. It is public member function. This function: Exchanges the content of the container by the content of variable, which is another unordered_multiset object containing elements of the same type but the sizes may differ. Af
3 min read
vector swap() in C++ In C++, std::vector::swap() is a built-in function used to exchange the contents to two vectors of same type. This function does not copy, move or swap the individual elements, instead, it swaps the internal pointers to the dynamically allocated array of both vectors and updates the size accordingly
3 min read