https://www.codewars.com/kata/binary-operations-number-1/train/csharp
Your work is to write a method that takes a value and an index, and returns the value with the bit at given index flipped.
The bits are numbered from the least significant bit (index 1).
Example:
FlipBit(15,4) == 7 // 15 in binary is 1111, after flipping 4th bit, it becomes 0111, i.e. 7
FlipBit(15,5) == 31 // 15 in binary is 1111, 5th bit is 0, after flipping, it becomes 11111, i.e., 31
using System; public class Flip { public static int FlipBit(int value, int bitIndex) { string str = Convert.ToString(value, 2).PadLeft(32,‘0‘); var array = str.ToCharArray(); int index = 32 - bitIndex; if (array[index] == ‘0‘) { array[index] = ‘1‘; } else { array[index] = ‘0‘; } str = string.Join(string.Empty,array); return Convert.ToInt32(str,2); } }
对于给定的value，反转index位置上对应的bit。index从最右边开始为第一位。
using System; public class Flip { public static int FlipBit(int value, int bitIndex) { int Mask = 1 << (bitIndex - 1); return value ^ Mask; } }
原文：http://www.cnblogs.com/chucklu/p/6413844.html