package mainimport ("fmt"
)/*
需求：实现用户用户特权，可以满足下面1个或多个条件
1. 红名
2. 达人
3. Vip会员
4. vip超级会员
5. 蓝钻用户
6. 红钻用户实现方法一：可以根据数据库字段，每个特权用一个字段，进行判断
缺点：每增加一个特权，要进行表字段扩展，代码修改实现方法二：用一个字段表示多个特权，这个方式需要用到位操作概念假设定义一个8位无符号int，它的二进制表示如下，每个位置用0、1表示红钻   蓝钻  超级vip  vip   达人   红名
0      0      0      0      0      0      0      0一、设置其中一位为1
用1 左移 n 与目标数做 或操作二、判断其中一位是否等于1
用1 左移 n 与目标数做 &操作三、清除其中一位
用1 左移 n 与目标数做 异或操作代码实现如下：*/const (HongMing  = 1 << 0DaRen     = 1 << 1Vip       = 1 << 2SuperVip  = 1 << 3LanZhuan  = 1 << 4HongZhuan = 1 << 5
)type User struct {name stringflag uint8
}func set_flag(user User, isSet bool, flag uint8) User {if isSet == true {user.flag = user.flag | flag} else {user.flag = user.flag ^ flag}return user
}func is_set_flag(user User, flag uint8) bool {result := user.flag & flagreturn result == flag
}func auth() {var user Useruser.name = "test01"user.flag = 0result := is_set_flag(user, HongMing)fmt.Printf("user is hongming:%t\n", result)user = set_flag(user, true, HongMing)result = is_set_flag(user, HongMing)fmt.Printf("user is hongming:%t\n", result)//user = set_flag(user, false, HongMing)//result = is_set_flag(user, HongMing)//fmt.Printf("user is hongming:%t\n", result)fmt.Printf("%v\n", user.flag)result = is_set_flag(user, DaRen)fmt.Printf("user is DaRen:%t\n", result)user = set_flag(user, true, DaRen)result = is_set_flag(user, DaRen)fmt.Printf("user is DaRen:%t\n", result)//user = set_flag(user, false, DaRen)//result = is_set_flag(user, DaRen)//fmt.Printf("user is DaRen:%t\n", result)fmt.Printf("%v\n", user.flag)result = is_set_flag(user, Vip)fmt.Printf("user is Vip:%t\n", result)user = set_flag(user, true, Vip)result = is_set_flag(user, Vip)fmt.Printf("user is Vip:%t\n", result)//user = set_flag(user, false, Vip)//result = is_set_flag(user, Vip)//fmt.Printf("user is Vip:%t\n", result)fmt.Printf("%v\n", user.flag)result = is_set_flag(user, SuperVip)fmt.Printf("user is SuperVip:%t\n", result)user = set_flag(user, true, SuperVip)result = is_set_flag(user, SuperVip)fmt.Printf("user is SuperVip:%t\n", result)//user = set_flag(user, false, SuperVip)//result = is_set_flag(user, SuperVip)//fmt.Printf("user is SuperVip:%t\n", result)fmt.Printf("%v\n", user.flag)result = is_set_flag(user, LanZhuan)fmt.Printf("user is LanZhuan:%t\n", result)user = set_flag(user, true, LanZhuan)result = is_set_flag(user, LanZhuan)fmt.Printf("user is LanZhuan:%t\n", result)//user = set_flag(user, false, LanZhuan)//result = is_set_flag(user, LanZhuan)//fmt.Printf("user is LanZhuan:%t\n", result)fmt.Printf("%v\n", user.flag)result = is_set_flag(user, HongZhuan)fmt.Printf("user is HongZhuan:%t\n", result)user = set_flag(user, true, HongZhuan)result = is_set_flag(user, HongZhuan)fmt.Printf("user is HongZhuan:%t\n", result)//user = set_flag(user, false, HongZhuan)//result = is_set_flag(user, HongZhuan)//fmt.Printf("user is HongZhuan:%t\n", result)fmt.Printf("%v\n", user.flag)}func main() {auth()
}