Set the rightmost off bit

Write a program that sets the rightmost 0 bit of an integer. 
Examples :

Input:  12 (00...01100)
Output: 13 (00...01101)

Input:  7 (00...00111)
Output: 15 (00...01111)

If we add 1 to a number, all set bits after rightmost unset (or zero bit) become 0 and the rightmost unset bit becomes 1.

C++

// CPP program to set the rightmost unset bit
#include<iostream>
using namespace std;

int setRightmostUnsetBit(int n)
{
    // If all bits are set
    if ((n & (n + 1)) == 0)
        return n;

    // Set rightmost 0 bit
    return n | (n+1);
}

// Driver program to test above
int main()
{
    int n = 21;
    cout << setRightmostUnsetBit(n);
    return 0;
}

Java

//Java  program to set the rightmost unset bit

public class GFG {

    static int setRightmostUnsetBit(int n)
    {
     // If all bits are set
     if ((n & (n + 1)) == 0)
         return n;

     // Set rightmost 0 bit
     return n | (n+1);
    }

    //Driver program to test above
    public static void main(String[] args) {

         int n = 21;
         System.out.println(setRightmostUnsetBit(n));
    }

}

Python 3

# Python3 program to set the
# rightmost unset bit

def setRightmostUnsetBit(n) :

    # If all bits are set
    if n & (n + 1) == 0 :
        return n

    # Set rightmost 0 bit
    return n | (n+1)

# Driver code
if __name__ == "__main__" :

    n = 21
    print(setRightmostUnsetBit(n))

# This code is contributed
# by ANKITRAI1

C#

// C# program to set the rightmost unset bit

using System;

public class GFG {

    static int setRightmostUnsetBit(int n)
    {
     // If all bits are set
     if ((n & (n + 1)) == 0)
         return n;

     // Set rightmost 0 bit
     return n | (n+1);
    }

    //Driver program to test above
    public static void Main() {

         int n = 21;
         Console.WriteLine(setRightmostUnsetBit(n));
    }

}

PHP

<?php
// PHP program to set the
// rightmost unset bit
function setRightmostUnsetBit($n)
{
    // If all bits are set
    if (($n & ($n + 1)) == 0)
        return $n;

    // Set rightmost 0 bit
    return $n | ($n + 1);
}

// Driver Code
$n = 21;
echo setRightmostUnsetBit($n);

// This code is contributed
// by Shivi_Aggarwal
?>

Javascript

<script>
// JavaScript program to set the rightmost unset bit
function setRightmostUnsetBit(n)
{
    // If all bits are set
    if ((n & (n + 1)) == 0)
        return n;

    // Set rightmost 0 bit
    return n | (n + 1);
}

// Driver program to test above
    let n = 21;
    document.write(setRightmostUnsetBit(n));

// This code is contributed by Manoj.
</script>

Output:

23

Time Complexity: O(1)

Auxiliary Space: O(1)