Swap all the pair of bits in a byte. Before swapping: 11-10-11-01 After swapping: 11-01-11-10
Examples:
Input : 00000010 Output : 00000001 Input : 00000100 Output : 00001000
Approach:
x = ((x & 0b10101010) >> 1) | ((x & 0b01010101) <> 1 extracts the high bit position and shifts it to the low bit position.
Similarly the expression (x & 0b01010101) << 1 extracts the low bit from each pair and shifts it to the high bit position.
The two parts are then combined using bitwise-OR.
x= 00011010
((x & 0b10101010) >> 1) = 00001010 >> 1
= 00000101
((x & 0b01010101) << 1) = 00010000 <> 1) | ((x & 0b01010101) << 1) = 00100101
Below is the implementation of the above:
Note: This solution works for only 8 bit.
C++
// C++ program to swap every two bits in a byte. #include<bits/stdc++.h> using namespace std; unsigned int swapBitsInPair(unsigned int x) { // Extracting the high bit shift it to lowbit // Extracting the low bit shift it to highbit return ((x & 0b10101010) >> 1) | ((x & 0b01010101) << 1); } /* Driver function to test above function */int main() { unsigned int x = 4; cout << swapBitsInPair(x); return 0; } |
Java
// Java program to swap every // two bits in a byte. import java.util.*; class GFG { static int swapBitsInPair( int x) { // Extracting the high bit shift it to lowbit // Extracting the low bit shift it to highbit return ((x & 0b10101010) >> 1) | ((x & 0b01010101) << 1); } // Driver Function public static void main(String[] args) { int x = 4; System.out.print(swapBitsInPair(x)); } } // This code is contributed by Gitanjali. |
Python3
# Python program to swap every # two bits in a byte. import math def swapBitsInPair( x): # Extracting the high bit shift it to lowbit # Extracting the low bit shift it to highbit return ((x & 0b10101010) >> 1) or ((x & 0b01010101) << 1) # driver Function x = 4; print(swapBitsInPair(x)) # This code is contributed by Gitanjali. |
C#
// C# program to swap every two bits in a byte. using System; public class GFG{ static uint swapBitsInPair(uint x) { // Extracting the high bit shift it to lowbit // Extracting the low bit shift it to highbit return ((x & 010101010) >> 1) | ((x & 001010101) << 1); } // Driver function to test above function static public void Main () { uint x = 4; Console.WriteLine(swapBitsInPair(x)); } } // This code is contributed by vt_m. |
PHP
<?php // PHP program to swap every // two bits in a byte. function swapBitsInPair($x) { // Extracting the high bit // shift it to lowbit // Extracting the low bit // shift it to highbit return (($x & 0b10101010) >> 1) | (($x & 0b01010101) << 1); } // Driver Code $x = 4; echo swapBitsInPair($x); // This code is contributed by mits ?> |
Output:
8
Reference:
https://stackoverflow.com/questions/4788799/swap-every-pair-of-bits-in-byte
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