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或许编程的朋友都曾经遇到过比特位的翻转，这儿有一段小程序或许能参考一下:)
其实思想很简单，先对各个比特位进行两两交换，然后二二交换，然后四四交换，然后八八交换，最后前后对换。
unsigned int
reverse(register unsigned int x)
{
register unsigned int y = 0x55555555;
x = (((x >> 1) & y) | ((x & y) << 1));
y = 0x33333333;
x = (((x >> 2) & y) | ((x & y) << 2));
y = 0x0f0f0f0f;
x = (((x >> 4) & y) | ((x & y) << 4));
y = 0x00ff00ff;
x = (((x >> 8) & y) | ((x & y) << 8));
return((x >> 16) | (x << 16));
}
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