bit_reverse.rar_reverse bit

#include <stdio.h> #include <math.h> int main() { #ifdef myversion int iHigh = 0; int iLow = 0; int result = 0; int test = 25; int iLen = sizeof(int) * 8; int i; //处理低位,把其转置到高位 for ( i = 0; i < iLen / 2 ; i++) { iHigh = test & (int)pow(2, i); iHigh <<= (iLen - 1 - i * 2); result |= iHigh; } //处理高位,转到低位 for ( i = iLen / 2; i < iLen ; i++) { //后来发现原来pow(2, X)可以用<<2来代替 iLow = test & (int)pow(2 ,i); iLow >>= (iLen - i * 2); result |= iLow; } #endif //version of book,so beutiful //利用两个变量的左移与右移,而不需要复杂的运算 int i; int test = 25; int result = 0; for ( i = 1; i != 0; i <<= 1 ) { result <<= 1; if ( test & 1 ) { result |= 1; } test >>= 1; } printf("%u", result); return 0; }