Set the rightmost unset bit

Given a non-negative number n. The problem is to set the rightmost unset bit in the binary representation of n

Examples:

Input : 21
Output : 23
(21)10 = (10101)2
Rightmost unset bit is at position 2(from right) as
highlighted in the binary representation of 21.
(23)10 = (10111)2
The bit at position 2 has been set.

Input : 2
Output : 3

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

One method is discussed in this article

This post discusses another method.

Let the input number be n. n+1 would have all the bits flipped after the rightmost unset bit (including the unset bit). So, doing n|(n+1) would give us the required result.

C++

 #include    // sets the rightmost unset bit // of n and returns the result int fun(unsigned int n) {     return n | (n + 1); }    // Driver Code int main() {     int n = 5;     printf("The number after setting the");     printf(" rightmost unset bit %d", fun(n));     return 0; }

Java

 class GFG {            // sets the rightmost unset bit     // of n and returns the result     static int fun(int n)     {         return n | (n + 1);     }            // Driver Code     public static void main(String[] args)     {         int n = 5;         System.out.printf("The number "                   + "after setting the");         System.out.printf(" rightmost "               + " unset bit %d", fun(n));     } }    // This code is contributed by Smitha

Python3

 # sets the rightmost unset bit # of n and returns the result def fun(n):        return n | (n + 1)    # Driver Code n = 5 print("The number after setting the", end="") print(" rightmost unset bit ", fun(n))    # This code is contributed by Smitha

C#

 using System;    class GFG {            // sets the rightmost unset bit     // of n and returns the result     static int fun(int n)     {         return n | (n + 1);     }            // Driver Code     public static void Main()     {         int n = 5;         Console.Write("The number "             + "after setting the");         Console.Write(" rightmost "            + "unset bit "+ fun(n));     } }    // This code is contributed by Smitha

PHP



Output :

The number after setting the rightmost unset bit 7

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