[转载] C++位运算：将一个4字节整数的二进制表示中的001替换为011

#include <iostream>
#include <assert.h>

/**
* Key:
* * get someone bit: num & (mode1bit<<N)
* * check a few bits: num & (mode3bit<<shift) == What
*/
int replace(int num)
{
    unsigned int mode3bit = ;
    unsigned int mode1bit = ;
    int shift = ;
    int result = ;
    while (shift < )
    {
        while (shift <  && (num & (mode3bit<<shift)) != (<<shift))
        {
            result += (num & (mode1bit<<shift));
            shift++;
        }
        if (shift >= )
        {
            break;
        }
        else if ( - shift < )
        {
            result += (num & (mode3bit<<shift));
            break;
        }
        result += (<<shift);
        shift += ;

    }
    return result;
}