Skip to content
Related Articles
How to turn off a particular bit in a number?
• Difficulty Level : Easy
• Last Updated : 26 Apr, 2021

Given a number n and a value k, turn off the k’th bit in n. Please note that k = 1 means the rightmost bit.
Examples:

```Input:  n = 15, k = 1
Output: 14

Input:  n = 14, k = 1
Output: 14
The rightmost bit was already off, so no change.

Input:  n = 15, k = 2
Output: 13

Input:  n = 15, k = 3
Output: 11

Input:  n = 15, k = 4
Output: 7

Input:  n = 15, k >= 5
Output: 15 ```

The idea is to use bitwise <<, & and ~ operators. Using expression “~(1 << (k – 1))“, we get a number which has all bits set, except the k’th bit. If we do bitwise & of this expression with n, we get a number which has all bits same as n except the k’th bit which is 0.
Below is the implementation of above idea.

## C++

 `#include ``using` `namespace` `std;` `// Returns a number that has all bits same as n``// except the k'th bit which is made 0``int` `turnOffK(``int` `n, ``int` `k)``{``    ``// k must be greater than 0``    ``if` `(k <= 0) ``return` `n;` `    ``// Do & of n with a number with all set bits except``    ``// the k'th bit``    ``return` `(n & ~(1 << (k - 1)));``}` `// Driver program to test above function``int` `main()``{``    ``int` `n = 15;``    ``int` `k = 4;``    ``cout << turnOffK(n, k);``    ``return` `0;``}`

## Java

 `// Java program to turn off a particular bit in a number``import` `java.io.*;` `class` `TurnOff``{``    ``// Function to returns a number that has all bits same as n``    ``// except the k'th bit which is made 0``    ``static` `int` `turnOffK(``int` `n, ``int` `k)``    ``{``        ``// k must be greater than 0``        ``if` `(k <= ``0``)``            ``return` `n;`` ` `        ``// Do & of n with a number with all set bits except``        ``// the k'th bit``        ``return` `(n & ~(``1` `<< (k - ``1``)));``    ``}``    ` `    ``// Driver program``    ``public` `static` `void` `main (String[] args)``    ``{``        ``int` `n = ``15``;``        ``int` `k = ``4``;``        ``System.out.println(turnOffK(n, k));``    ``}``}``// Contributed by Pramod Kumar`

## Python3

 `# Returns a number that``# has all bits same as n``# except the k'th bit``# which is made 0` `def` `turnOffK(n,k):` `    ``# k must be greater than 0``    ``if` `(k <``=` `0``):``        ``return` `n`` ` `    ``# Do & of n with a number``    ``# with all set bits except``    ``# the k'th bit``    ``return` `(n & ~(``1` `<< (k ``-` `1``)))` ` ` `# Driver code``n ``=` `15``k ``=` `4``print``(turnOffK(n, k))` `# This code is contributed``# by Anant Agarwal.`

## C#

 `// C# program to turn off a``// particular bit in a number``using` `System;` `class` `GFG``{``    ` `    ``// Function to returns a number``    ``// that has all bits same as n``    ``// except the k'th bit which is``    ``// made 0``    ``static` `int` `turnOffK(``int` `n, ``int` `k)``    ``{``        ``// k must be greater than 0``        ``if` `(k <= 0)``            ``return` `n;` `        ``// Do & of n with a number``        ``// with all set bits except``        ``// the k'th bit``        ``return` `(n & ~ (1 << (k - 1)));``    ``}``    ` `    ``// Driver Code``    ``public` `static` `void` `Main ()``    ``{``        ``int` `n = 15;``        ``int` `k = 4;``        ``Console.Write(turnOffK(n, k));``    ``}``}` `// This code is contributed by Nitin Mittal.`

## PHP

 ``

## Javascript

 ``

Output:

`7`

Exercise: Write a function turnOnK() that turns the k’th bit on.
This article is contributed by Rahul Jain. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above

Attention reader! Don’t stop learning now. Get hold of all the important DSA concepts with the DSA Self Paced Course at a student-friendly price and become industry ready.  To complete your preparation from learning a language to DS Algo and many more,  please refer Complete Interview Preparation Course.

In case you wish to attend live classes with industry experts, please refer DSA Live Classes

My Personal Notes arrow_drop_up