交换奇偶bit

Write a program to swap odd and even bits in an integer with as few instructions as possible (e.g., bit 0 and bit 1 are swapped, bit 2 and bit 3 are swapped, etc).

去掉奇数位,将剩下的偶数位左移 ==>x
去掉偶数位,将剩下的奇数位右移 ==>y
结果就是x|y

1. 
   
2. int FastSwap(int n)
   
3. {
   
4.         return ((n & 0x55555555) << 1) | ((n & 0xaaaaaaaa) >> 1);
   
5. }
   

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