function to count the number of "1" of one byte

function to count the number of "1" of one byte ,for example 5(0101)has two "1"

经常遇到的面试题，毫无疑问需要借助位操作：

unsigned int bitCount (unsigned int value) {
unsigned int count = 0;
while (value > 0) { // until all bits are zero
//if ((value & 1) == 1) // check lower bit
// count++;
count += value & 0x1;
value >>= 1; // shift bits, removing lower bit
//printf("value:%d, count:%d\n", value, count);
}
return count;
}