C#: القوائم والهيكلية

enum Season
{
    Spring,
    Summer,
    Autumn,
    Winter
}

class Program
{
    static void Main()
    {
        Season current = Season.Autumn;
        System.Console.WriteLine(current);
        System.Console.WriteLine((int)current);
    }
}

Autumn
2

enum Priority : byte
{
    Low = 1,
    Medium = 2,
    High = 3
}

enum HttpStatusCode
{
    OK = 200,
    NotFound = 404,
    InternalServerError = 500
}

class Program
{
    static void Main()
    {
        Priority p = Priority.High;
        System.Console.WriteLine((byte)p);
        System.Console.WriteLine((int)HttpStatusCode.NotFound);
    }
}

3
404

enum Season
{
    Spring,
    Summer,
    Autumn,
    Winter
}

class Program
{
    static void Main()
    {
        Season s = Season.Spring;
        int value = (int)s;
        System.Console.WriteLine(value);

        Season fromInt = (Season)2;
        System.Console.WriteLine(fromInt);
    }
}

0
Autumn

enum Season
{
    Spring,
    Summer,
    Autumn,
    Winter
}

class Program
{
    static void Main()
    {
        Season parsed = (Season)Enum.Parse(typeof(Season), "Summer");
        System.Console.WriteLine(parsed);

        bool ok = Enum.TryParse<Season>("Winter", out Season result);
        System.Console.WriteLine($"{ok}, {result}");

        string name = Enum.GetName(typeof(Season), 2);
        System.Console.WriteLine(name);

        foreach (Season s in Enum.GetValues(typeof(Season)))
        {
            System.Console.WriteLine($"{s} = {(int)s}");
        }

        System.Console.WriteLine(Enum.IsDefined(typeof(Season), 1));
        System.Console.WriteLine(Enum.IsDefined(typeof(Season), 99));
    }
}

Summer
True, Winter
Autumn
Spring = 0
Summer = 1
Autumn = 2
Winter = 3
True
False

struct Point
{
    public int X;
    public int Y;

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

    public override string ToString()
    {
        return $"({X}, {Y})";
    }
}

class Program
{
    static void Main()
    {
        Point p1 = new Point(3, 4);
        Point p2 = p1;
        p2.X = 10;
        System.Console.WriteLine(p1);
        System.Console.WriteLine(p2);
    }
}

(3, 4)
(10, 4)

struct PointStruct
{
    public int X;
    public int Y;
}

class PointClass
{
    public int X;
    public int Y;
}

class Program
{
    static void Main()
    {
        PointStruct s1 = new PointStruct();
        PointStruct s2 = s1;
        s2.X = 5;
        System.Console.WriteLine($"struct: s1.X={s1.X}, s2.X={s2.X}");

        PointClass c1 = new PointClass();
        PointClass c2 = c1;
        c2.X = 5;
        System.Console.WriteLine($"class: c1.X={c1.X}, c2.X={c2.X}");
    }
}

struct: s1.X=0, s2.X=5
class: c1.X=5, c2.X=5

readonly struct Point
{
    public int X { get; }
    public int Y { get; }

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

    public double DistanceTo(Point other)
    {
        int dx = X - other.X;
        int dy = Y - other.Y;
        return System.Math.Sqrt(dx * dx + dy * dy);
    }
}

class Program
{
    static void Main()
    {
        Point p1 = new Point(3, 4);
        Point p2 = new Point(0, 0);
        System.Console.WriteLine(p1.DistanceTo(p2));
    }
}

5

public class Point : IEquatable<Point>
{
    public int X { get; }
    public int Y { get; }
    public Point(int x, int y)
    {
        X = x;
        Y = y;
    }
    public Point With(int? x = null, int? y = null)
    {
        return new Point(x ?? this.X, y ?? this.Y);
    }
    public bool Equals(Point other)
    {
        return other != null && X == other.X && Y == other.Y;
    }
    public override bool Equals(object obj) => Equals(obj as Point);
    public override int GetHashCode() => System.HashCode.Combine(X, Y);
    public override string ToString() => $"Point {{ X = {X}, Y = {Y} }}";
}

class Program
{
    static void Main()
    {
        Point p1 = new Point(1, 2);
        Point p2 = new Point(1, 2);
        System.Console.WriteLine(p1 == p2);
        System.Console.WriteLine(p1.With(x: 10));
    }
}

True
Point { X = 10, Y = 2 }