逻辑运算符 #

bool a = true;
bool b = true;
bool result = a && b;

bool c = true;
bool d = false;
bool result2 = c && d;

int x = 10;
bool result = x > 5 && x++ < 20;

int y = 10;
bool result2 = y > 20 && y++ < 30;

string name = null;

if (name != null && name.Length > 0)
{
    Console.WriteLine(name);
}

int? age = null;
if (age.HasValue && age.Value >= 18)
{
    Console.WriteLine("成年人");
}

bool a = true;
bool b = false;
bool result = a || b;

bool c = false;
bool d = false;
bool result2 = c || d;

int x = 10;
bool result = x < 5 || x++ > 5;

int y = 10;
bool result2 = y < 20 || y++ > 20;

int age = 16;
bool hasPermission = false;

if (age >= 18 || hasPermission)
{
    Console.WriteLine("允许进入");
}

string role = "admin";
if (role == "admin" || role == "manager")
{
    Console.WriteLine("有管理权限");
}

bool a = true;
bool notA = !a;

bool b = false;
bool notB = !b;

bool isLoggedIn = false;

if (!isLoggedIn)
{
    Console.WriteLine("请先登录");
}

string name = "";
if (string.IsNullOrEmpty(name))
{
    Console.WriteLine("名称不能为空");
}

if (!string.IsNullOrEmpty(name))
{
    Console.WriteLine($"欢迎，{name}");
}

bool a = true;
bool b = false;
bool result = a ^ b;

bool c = true;
bool d = true;
bool result2 = c ^ d;

bool isWeekend = true;
bool isHoliday = false;

if (isWeekend ^ isHoliday)
{
    Console.WriteLine("只有一个是休息日");
}

bool a = true;
a = !a;
a = a ^ true;

bool Method1()
{
    Console.WriteLine("Method1 called");
    return true;
}

bool Method2()
{
    Console.WriteLine("Method2 called");
    return false;
}

bool result1 = Method1() && Method2();
bool result2 = Method1() & Method2();

bool result3 = Method1() || Method2();
bool result4 = Method1() | Method2();

bool flag1 = false;
bool flag2 = false;

if (flag1 & flag2)
{
}

if (flag1 | flag2)
{
}

int age = 25;
bool hasLicense = true;
bool hasInsurance = true;

if (age >= 18 && hasLicense && hasInsurance)
{
    Console.WriteLine("可以驾驶");
}

int score = 85;
int attendance = 90;

if (score >= 60 || attendance >= 80)
{
    Console.WriteLine("通过考核");
}

int age = 25;
bool isMember = true;
bool hasCoupon = false;

if ((age >= 18 && age <= 65) && (isMember || hasCoupon))
{
    Console.WriteLine("享受优惠");
}

bool a = true;
bool b = false;
bool c = true;

bool result = a && (b || c);

bool a = true;
bool b = false;

bool result1 = !(a && b);
bool result2 = !a || !b;

bool result3 = !(a || b);
bool result4 = !a && !b;

bool? a = true;
bool? b = false;
bool? c = null;

bool? andResult = a & b;
bool? orResult = a | b;

public static bool ValidateUser(string username, string password, int age)
{
    return !string.IsNullOrEmpty(username) 
        && username.Length >= 3 
        && !string.IsNullOrEmpty(password) 
        && password.Length >= 6 
        && age >= 18;
}

public static bool HasAccess(User user, string resource)
{
    return user != null 
        && user.IsActive 
        && (user.Role == "Admin" || user.Permissions.Contains(resource));
}

public static bool IsValidRange(int value, int? min = null, int? max = null)
{
    return (!min.HasValue || value >= min.Value) 
        && (!max.HasValue || value <= max.Value);
}

public static bool IsValidInput(string input)
{
    return !string.IsNullOrWhiteSpace(input) 
        && input.Length >= 2 
        && input.Length <= 50;
}

if (obj != null && obj.IsValid)
{
}

if (string.IsNullOrEmpty(name) || name.Length > 100)
{
}

if (isValid == true)
{
}

if (isValid)
{
}

if (isValid == false)
{
}

if (!isValid)
{
}

bool isAdult = age >= 18;
bool hasValidId = id != null && id.Length > 0;
bool hasPaymentMethod = creditCard != null || paypal != null;

if (isAdult && hasValidId && hasPaymentMethod)
{
    ProcessOrder();
}