Turn off the rightmost set bit

Write a program that unsets the rightmost set bit of an integer.

Examples :

Input:  12 (00...01100)
Output: 8 (00...01000)

Input:  7 (00...00111)
Output: 6 (00...00110)

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

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

C++

#include <bits/stdc++.h> 
using namespace std; 
  
// unsets the rightmost set bit  
// of n and returns the result  
int fun(unsigned int n)  
{  
    return n & (n - 1);  
}  
  
// Driver Code  
int main()  
{  
    int n = 7;  
    cout<<"The number after unsetting the";  
    cout<<" rightmost set bit "<<fun(n);  
    return 0;  
}  
  
  
  
//This code is contributed by rathbhupendra 

C

#include <stdio.h> 
  
// unsets the rightmost set bit 
// of n and returns the result 
int fun(unsigned int n) 
{ 
    return n & (n - 1); 
} 
  
// Driver Code 
int main() 
{ 
    int n = 7; 
    printf("The number after unsetting the"); 
    printf(" rightmost set bit %d", fun(n)); 
    return 0; 
} 

Java

// Java program to unset the 
// rightmost set bit of an integer. 
  
class GFG { 
  
    /* unsets the rightmost set bit 
     of n and returns the result */
    static int fun(int n) 
    { 
        return n & (n - 1); 
    } 
  
    // Driver code 
    public static void main(String arg[]) 
    { 
        int n = 7; 
        System.out.print("The number after unsetting "
                         + "the rightmost set bit " + fun(n)); 
    } 
} 
  
// This code is contributed by Anant Agarwal. 

Python3

# unsets the rightmost set bit 
# of n and returns the result  
def fun(n): 
  
     return n & (n-1) 
  
# Driver code 
  
n = 7
print("The number after unsetting the rightmost set bit", fun(n)) 
  
# This code is contributed 
# by Anant Agarwal. 

C#

// C# program to unset the 
// rightmost set bit of an integer. 
using System; 
  
class GFG { 
  
    /* unsets the rightmost set bit 
    of n and returns the result */
    static int fun(int n) 
    { 
        return n & (n - 1); 
    } 
  
    // Driver code 
    public static void Main() 
    { 
        int n = 7; 
        Console.Write("The number after unsetting "
                      + "the rightmost set bit " + fun(n)); 
    } 
} 
  
// This code is contributed by Sam007 

PHP

<?php 
// unsets the rightmost set bit  
// of n and returns the result  
function fun($n) 
{ 
return $n & ($n - 1); 
}  
  
// Driver Code 
$n = 7; 
echo "The number after unsetting the". 
     " rightmost set bit ", fun($n); 
  
// This code is contributed by vt_m. 
  
?> 

Output :

The number after unsetting the rightmost set bit 6

Please write comments if you find the above code/algorithm incorrect, or find better ways to solve the same problem

My Personal Notes

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

C++

C

Java

Python3

C#

PHP

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