Question

How to reverse the bits of a number in C#

Answer 1

using System;
using System.Linq;

class Program
{
    static uint ReverseBits(uint n) {
        string bin = Convert.ToString(n, 2).PadLeft(32, '0');
        string rev = new string(bin.Reverse().ToArray());
        
        return Convert.ToUInt32(rev, 2);
    }

    static string Bits(uint n) {
        string bin = Convert.ToString(n, 2).PadLeft(32, '0');
        
        return string.Join(" ", Enumerable.Range(0, 4)
            .Select(i => bin.Substring(i * 8, 8)));
    }

    static void Main()
    {
        uint a = 19;
        uint b = 3;

        uint ra = ReverseBits(a);
        uint rb = ReverseBits(b);

        Console.WriteLine("Original 19: " + Bits(a));
        Console.WriteLine("Reversed 19: " + Bits(ra));
        Console.WriteLine();
        Console.WriteLine("Original 3:  " + Bits(b));
        Console.WriteLine("Reversed 3:  " + Bits(rb));
    }
}



/*
run:

Original 19: 00000000 00000000 00000000 00010011
Reversed 19: 11001000 00000000 00000000 00000000

Original 3:  00000000 00000000 00000000 00000011
Reversed 3:  11000000 00000000 00000000 00000000

*/

 

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