الهياكل والتعدادات (Struct و Enum)

struct Point
{
    public int X;
    public int Y;

    public Point(int x, int y) { X = x; Y = y; }
}

Point p1 = new Point(1, 2);
Point p2 = p1;      // نسخة كاملة، ليست نفس البيانات
p2.X = 99;

Console.WriteLine(p1.X);   // 1 — لم يتأثّر
Console.WriteLine(p2.X);   // 99

enum Season
{
    Spring,   // 0
    Summer,   // 1
    Autumn,   // 2
    Winter    // 3
}

Season current = Season.Autumn;

enum HttpStatus : ushort
{
    OK = 200,
    NotFound = 404,
    ServerError = 500
}

string Describe(Season s) => s switch
{
    Season.Spring => "ربيع",
    Season.Summer => "صيف",
    Season.Autumn => "خريف",
    Season.Winter => "شتاء",
    _ => "غير معروف"
};

int code = (int)HttpStatus.NotFound;        // 404
HttpStatus s = (HttpStatus)200;              // HttpStatus.OK
bool valid = Enum.IsDefined(typeof(HttpStatus), 999);   // false

[Flags]
enum FilePermission
{
    None = 0,
    Read = 1,
    Write = 2,
    Execute = 4
}

var p = FilePermission.Read | FilePermission.Write;
Console.WriteLine(p);                          // Read, Write
Console.WriteLine(p.HasFlag(FilePermission.Write));   // True