Toggling k-th bit of a number
For a given number n, if k-th bit is 0, then toggle it to 1 and if it is 1 then, toggle it to 0.
Examples :
Input : n = 5, k = 1 Output : 4 5 is represented as 101 in binary and has its first bit 1, so toggling it will result in 100 i.e. 4. Input : n = 2, k = 3 Output : 6 Input : n = 75, k = 4 Output : 67
Below are simple steps to find the value of k-th bit
1) Left shift given number 1 by k-1 to create a number that has only set bit as k-th bit. temp = 1 << (k-1) 2) Return bitwise XOR of temp and n. Since temp has only k-th bit set, doing XOR would toggle only this bit.
Example :
n = 75 and k = 4 temp = 1 << (k-1) = 1 << 3 = 8 Binary Representation of temp = 0..00001000 Binary Representation of n = 0..01001011 Bitwise XOR of two numbers = 0..01000011
C++
// CPP program to toggle k-th bit of n #include<iostream> using namespace std; int toggleKthBit( int n, int k) { return (n ^ (1 << (k-1))); } // Driver code int main() { int n = 5, k = 1; cout << toggleKthBit(n , k); return 0; } |
Java
// Java program to toggle // k-th bit of a number class Toggle { static int toggleKthBit( int n, int k) { return (n ^ ( 1 << (k- 1 ))); } // main function public static void main (String[] args) { int n = 5 , k = 1 ; System.out.println(toggleKthBit(n , k)); } } |
Python3
# Python3 code to toggle k-th bit of n def toggleKthBit(n, k): return (n ^ ( 1 << (k - 1 ))) # Driver code n = 5 k = 1 print ( toggleKthBit(n , k)) # This code is contributed by "Sharad_Bhardwaj". |
C#
// C# program to toggle // k-th bit of a number using System; class GFG { static int toggleKthBit( int n, int k) { return (n ^ (1 << (k-1))); } // main function public static void Main() { int n = 5, k = 1; Console.WriteLine(toggleKthBit(n , k)); } } //This code is contributed by Anant Agarwal. |
PHP
<?php // Php program to toggle k-th bit of n function toggleKthBit( $n , $k ) { return ( $n ^ (1 << ( $k - 1))); } // Driver code $n = 5; $k = 1; echo toggleKthBit( $n , $k ); // This code is contributed by Ajit ?> |
Javascript
<script> // Javascript program to toggle // k-th bit of a number function toggleKthBit(n, k) { return (n ^ (1 << (k-1))); } let n = 5, k = 1; document.write(toggleKthBit(n , k)); </script> |
Output :
4
Time Complexity : O(1)
Space Complexity : O(1)
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