# Number formed by the rightmost set bit in N

Given an integer N, the task is to find an integer M formed by taking the rightmost set bit in N i.e. the only set bit in M will be the rightmost set bit in N nd the rest of the bits will be unset.

Examples:

Input: N = 7
Output: 1
7 = 111, the number formed by the last set bit is 001 i.e. 1.

Input: N = 10
Output: 2
10 = 1010 -> 0010 = 2

Input: N = 16
Output: 16

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach:

• Store x = n & (n – 1) which will unset the first set bit from the right in n.
• Now, update n = n ^ x to set the changed bit and unset all the others which is the required integer.

Below is the implementation of the above approach:

## C++

 `// C++ implementation of the approach ` `#include ` `using` `namespace` `std; ` ` `  `// Function to return the integer formed ` `// by taking the rightmost set bit in n ` `int` `firstSetBit(``int` `n) ` `{ ` ` `  `    ``// n & (n - 1) unsets the first set ` `    ``// bit from the right in n ` `    ``int` `x = n & (n - 1); ` ` `  `    ``// Take xor with the original number ` `    ``// The position of the 'changed bit' ` `    ``// will be set and rest will be unset ` `    ``return` `(n ^ x); ` `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `    ``int` `n = 12; ` ` `  `    ``cout << firstSetBit(n); ` ` `  `    ``return` `0; ` `} `

## Java

 `// Java implementation of the approach ` `class` `geeks ` `{ ` `     `  `    ``// Function to return the integer formed  ` `    ``// by taking the rightmost set bit in n ` `    ``public` `static` `int` `firstSetBit(``int` `n) ` `    ``{ ` `         `  `        ``// n & (n - 1) unsets the first set  ` `        ``// bit from the right in n ` `        ``int` `x = n & (n-``1``); ` `         `  `        ``// Take xor with the original number  ` `        ``// The position of the 'changed bit'  ` `        ``// will be set and rest will be unset ` `        ``return` `(n ^ x); ` `    ``} ` `     `  `    ``// Driver Code ` `    ``public` `static` `void` `main (String[] args)  ` `    ``{ ` `        ``int` `n = ``12``; ` `        ``System.out.println(firstSetBit(n)); ` `    ``} ` `} ` ` `  `// This code is contributed by ` `// sanjeev2552 `

## Python3

 `# Python3 implementation of the approach ` ` `  `# Function to return the integer formed ` `# by taking the rightmost set bit in n ` `def` `firstSetBit(n): ` ` `  `    ``# n & (n - 1) unsets the first set ` `    ``# bit from the right in n ` `    ``x ``=` `n & (n ``-` `1``) ` ` `  `    ``# Take xor with the original number ` `    ``# The position of the 'changed bit' ` `    ``# will be set and rest will be unset ` `    ``return` `(n ^ x) ` ` `  `# Driver code ` `n ``=` `12` ` `  `print``(firstSetBit(n)) ` ` `  `# This code is contributed by mohit kumar 29 `

## C#

 `// C# implementation of the approach ` `using` `System; ` ` `  `class` `geeks ` `{ ` `     `  `    ``// Function to return the integer formed  ` `    ``// by taking the rightmost set bit in n ` `    ``public` `static` `int` `firstSetBit(``int` `n) ` `    ``{ ` `         `  `        ``// n & (n - 1) unsets the first set  ` `        ``// bit from the right in n ` `        ``int` `x = n & (n-1); ` `         `  `        ``// Take xor with the original number  ` `        ``// The position of the 'changed bit'  ` `        ``// will be set and rest will be unset ` `        ``return` `(n ^ x); ` `    ``} ` `     `  `    ``// Driver Code ` `    ``public` `static` `void` `Main ()  ` `    ``{ ` `        ``int` `n = 12; ` `        ``Console.WriteLine(firstSetBit(n)); ` `    ``} ` `} ` ` `  `// This code is contributed by ` `// anuj_67.. `

Output:

```4
```

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