[go语言算法] 求二进制整数中1的个数

package main

import "fmt"

func main()  {
    //count := getCountOfNotZero1(-1)
    //count := getCountofNotZero3(-1);
    count := getCountOfNotZero2(0)
    fmt.Println(count);
}

//只适合正数
func getCountOfNotZero1(num int)  int{
    count := 0;
    for ;num!=0 ;  {
        if num & 1>0 {
            count++
        }
        num = num >>1;
    }
    return count;
}

func getCountOfNotZero2(num int)  (count int){
    flag := 1;
    i := 2
    for num != 0 && i<=64 {
        if flag & num > 0 {
            count++
        }
        flag <<= 1
        i++;
        fmt.Println(num)
    }
    return
}

func getCountofNotZero3(num int) int {
    count := 0
    for num != 0 {
        num = num & (num-1)
        count++;
    }
    return count
}