C++关于二进制位操作小结

#include <iostream>
using namespace std;
//二进制位逆序。
int Grial(int x)
{
    int n = 32;
    int count = 0;
    while (n--)
    {
        count|= ((x&0x1) << n);
        x = ((unsigned)x >> 1);
    }
    return count;
}
int main()
{
    cout << Grial(1) << endl;
    return 0;
}


#include <iostream>
using namespace std;
//二进制位中的奇偶位互换。
int Grial(int x)
{
    int sum1 = x & 0x55555555;
    int sum2 = x & 0xaaaaaaaa;
    sum1 <<= 1;
    sum2 >>= 1;
    return sum1 | sum2;
}
int main()
{
    cout << Grial(6) << endl;
    return 0;
}


#include <iostream>
using namespace std;
//求两个数的和。

int Grial(int x, int y)
{
    if (!y)return x;

    //int ret = x^y;
    //-1%2=-1;

    int sum = x^y;
    int num = ((x&y)<<1);
    return Grial(sum,num);

}
int main()
{
    cout << Grial(3, 5) << endl;
    return 0;
}





#include <iostream>
using namespace std;
//推断一个数是不是2的n次方。
bool Grial(int x)
{
    return (x&(x - 1)) == 0;
}
int main()
{
    cout << Grial(4) << endl;
    return 0;
}




#include <iostream>
using namespace std;
//求二进制中1的个数。
int Grial(int x)
{
    int count = 0;
    while (x)
    {
        x = x&(x - 1);
        count++;
    }
    return count;
}
int main()
{
    cout << Grial(15) << endl;
}



#include <iostream>
using namespace std;
//求平均值。
int Grial(int x,int y)
{
    return (x&y) + ((x^y) >> 1);
}
int main()
{
    cout << Grial(20, 48) << endl;
    return 0;
}
#include <iostream>
using namespace std;
//求平均值。
int Grial(int x,int y)
{
    return x - (x - y) / 2;
}
int main()
{
    cout << Grial(3,9) << endl;
    return 0;
}