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# Toggle all even bits of a number

• Difficulty Level : Medium
• Last Updated : 07 Sep, 2021

Given a number, the task is to Toggle all even bit of a number
Examples:

```Input : 10
Output : 0
binary representation 1 0 1 0
after toggle          0 0 0 0

Input : 20
Output : 30
binary representation 1 0 1 0 0
after toggle          1 1 1 1 0```

1. First generate a number that contains even position bits.
2. Take XOR with the original number. Note that 1 ^ 1 = 0 and 1 ^ 0 = 1.
Let’s understand this approach with below code.

## C++

 `// CPP code to Toggle all even``// bit of a number``#include ``using` `namespace` `std;` `// Returns a number which has all even``// bits of n toggled.``int` `evenbittogglenumber(``int` `n)``{``    ``// Generate number form of 101010``    ``// ..till of same order as n``    ``int` `res = 0, count = 0;``    ``for` `(``int` `temp = n; temp > 0; temp >>= 1) {` `        ``// if bit is even then generate``        ``// number and or with res``        ``if` `(count % 2 == 1)``            ``res |= (1 << count);     ` `        ``count++;``    ``}` `    ``// return toggled number``    ``return` `n ^ res;``}` `// Driver code``int` `main()``{``    ``int` `n = 11;``    ``cout << evenbittogglenumber(n);``    ``return` `0;``}`

## Java

 `// Java code to Toggle all``// even bit of a number``import` `java.io.*;` `class` `GFG {``    ` `    ``// Returns a number which has``    ``// all even bits of n toggled.``    ``static` `int` `evenbittogglenumber(``int` `n)``    ``{``        ``// Generate number form of 101010``        ``// ..till of same order as n``        ``int` `res = ``0``, count = ``0``;``        ``for` `(``int` `temp = n; temp > ``0``;``                               ``temp >>= ``1``)``        ``{``            ``// if bit is even then generate``            ``// number and or with res``            ``if` `(count % ``2` `== ``1``)``                ``res |= (``1` `<< count);     ``     ` `            ``count++;``        ``}``     ` `        ``// return toggled number``        ``return` `n ^ res;``    ``}``     ` `    ``// Driver code``    ``public` `static` `void` `main(String args[])``    ``{``        ``int` `n = ``11``;``        ``System.out.println(evenbittogglenumber(n));``    ``}``}` `// This code is contributed by Nikita Tiwari.`

## Python3

 `# Python code to Toggle all``# even bit of a number` `# Returns a number which has all even``# bits of n toggled.``def` `evenbittogglenumber(n) :` `    ``# Generate number form of 101010``    ``# ..till of same order as n``    ``res ``=` `0``    ``count ``=` `0``    ``temp ``=` `n` `    ``while` `(temp > ``0``) :``        ` `        ``# if bit is even then generate``        ``# number and or with res``        ``if` `(count ``%` `2` `=``=` `1``) :``            ``res ``=` `res | (``1` `<< count)    `` ` `        ``count ``=` `count ``+` `1``        ``temp >>``=` `1``        ` ` ` `    ``# return toggled number``    ``return` `n ^ res`` ` `# Driver code``n ``=` `11``print``(evenbittogglenumber(n))` `#This code is contributed by Nikita Tiwari.`

## C#

 `// C# code to Toggle all``// even bit of a number``using` `System;`` ` `class` `GFG {``     ` `    ``// Returns a number which has``    ``// all even bits of n toggled.``    ``static` `int` `evenbittogglenumber(``int` `n)``    ``{``        ``// Generate number form of 101010``        ``// ..till of same order as n``        ``int` `res = 0, count = 0;``        ` `        ``for` `(``int` `temp = n; temp > 0;``                               ``temp >>= 1)``        ``{``            ``// if bit is even then generate``            ``// number and or with res``            ``if` `(count % 2 == 1)``                ``res |= (1 << count);     ``      ` `            ``count++;``        ``}``      ` `        ``// return toggled number``        ``return` `n ^ res;``    ``}``      ` `    ``// Driver code``    ``public` `static` `void` `Main()``    ``{``        ` `        ``int` `n = 11;``        ` `        ``Console.WriteLine(evenbittogglenumber(n));``    ``}``}`` ` `// This code is contributed by Anant Agarwal.`

## PHP

 ` 0; ``\$temp` `>>= 1)``    ``{` `        ``// if bit is even then generate``        ``// number and or with res``        ``if` `(``\$count` `% 2 == 1)``            ``\$res` `|= (1 << ``\$count``);    ` `        ``\$count``++;``    ``}` `    ``// return toggled number``    ``return` `\$n` `^ ``\$res``;``}` `    ``// Driver code``    ``\$n` `= 11;``    ``echo` `evenbittogglenumber(``\$n``);` `// This code is contributed by mits``?>`

## Javascript

 ``

Output:

`1`

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