判断1个字节中被置1的位的个数

#include <iostream>

using namespace std;

size_t calcHasOneBit(char ch)
{
    size_t count = 0, i = 0;
    char val = 0;

    for (i = 0; i < 8; i++) {
        val = ch >> i;
        val &= 0x01;
        if (val) {
            count++;
        }
    }

    return count;
}

int main(int argc, char * argv[])
{
    cout << calcHasOneBit(‘a‘) << endl;

    return 0;
}