Program to toggle K-th bit of a number N
Given a number N, the task is to clear the K-th bit of this number N. If K-th bit is 0, then set it to 1 and if it is 1 then set it to 0.
Examples:
Input: N = 5, K = 2 Output: 7 5 is represented as 101 in binary and has its second bit 0, so toggling it will result in 111 i.e. 7. Input: N = 5, K = 1 Output: 4 5 is represented as 101 in binary and has its first bit is 1, so toggling it will result in 100 i.e. 4.
Approach:
- Since XOR of unset and set bit results in a set bit and XOR of a set and set bit results in an unset bit. Hence performing bitwise XOR of any bit with a set bit results in toggle of that bit, i.e.
Any bit <bitwise XOR> Set bit = Toggle which means, 0 ^ 1 = 1 1 ^ 1 = 0
- So in order to toggle a bit, performing a bitwise XOR of the number with a reset bit is the best idea.
n = n ^ 1 << k OR n ^= 1 << k where k is the bit that is to be cleared
Below is the implementation of the above approach:
C++
// C++ program to toggle K-th bit of a number N #include<bits/stdc++.h> using namespace std; // Function to toggle the kth bit of n int toggleBit( int n, int k) { return (n ^ (1 << (k - 1))); } // Driver code int main() { int n = 5, k = 2; cout << toggleBit(n, k) << endl; return 0; } // This code is contributed by noob2000 |
C
// C program to toggle K-th bit of a number N #include <stdio.h> // Function to toggle the kth bit of n int toggleBit( int n, int k) { return (n ^ (1 << (k - 1))); } // Driver code int main() { int n = 5, k = 2; printf ( "%d\n" , toggleBit(n, k)); return 0; } |
Java
// Java program to toggle K-th bit of a number N class GFG { // Function to toggle the kth bit of n static int toggleBit( int n, int k) { return (n ^ ( 1 << (k - 1 ))); } // Driver code public static void main(String []args) { int n = 5 , k = 2 ; System.out.printf( "%d\n" , toggleBit(n, k)); } } // This code is contributed by Rajput-Ji |
Python3
# Python3 program to clear K-th bit # of a number N # Function to toggle the kth bit of n def toggleBit(n, k) : return (n ^ ( 1 << (k - 1 ))); # Driver code if __name__ = = "__main__" : n = 5 ; k = 2 ; print (toggleBit(n, k)); # This code is contributed by AnkitRai01 |
C#
// C# program to toggle K-th bit of a number N using System; class GFG { // Function to toggle the kth bit of n static int toggleBit( int n, int k) { return (n ^ (1 << (k - 1))); } // Driver code public static void Main(String []args) { int n = 5, k = 2; Console.WriteLine( "{0}" , toggleBit(n, k)); } } // This code is contributed by PrinciRaj1992 |
Javascript
<script> // Javascript program to toggle K-th bit of a number N // Function to toggle the kth bit of n function toggleBit(n, k) { return (n ^ (1 << (k - 1))); } // Driver code var n = 5, k = 2; document.write( toggleBit(n, k)); // This code is contributed by famously. </script> |
Output:
7
Time Complexity: O(1)
Auxiliary Space: O(1)
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