C# switch

public static void test0()
{
    int x = 2;

    switch (x)
    {
        case 1:
            Console.WriteLine("Un");
            goto case 2;
        case 2:
            Console.WriteLine("Deux");
            break;
        default:
            Console.WriteLine("Autre");
            break;
    }
}
    

        // Switch avec goto
public static void test1()
{
    int x = 2;
    switch (x)
    {
        case 1:
            Console.WriteLine("Un");
            goto case 2;
        case 2:
            Console.WriteLine("Deux");
            break;
        default:
            Console.WriteLine("Autre");
            break;
    }

}
    

// Switch expression
public static void test2()
{
    int x = 1;

    string result = x switch
    {
        1 => "Un",
        2 => "Deux",
        _ => "Autre"
    };
    Console.WriteLine(result);
}
    

// Pattern matching
public static void test3()
{
    object obj = 52;

    switch (obj)
    {
        case int i when i > 0:
            Console.WriteLine($"Nombre positif : {i}");
            break;
        case string s:
            Console.WriteLine($"Chaîne : {s}");
            break;
        case null:
            Console.WriteLine("Null");
            break;
        default:
            Console.WriteLine("Autre type");
            break;
    }
}
    

// Switch expression
public static void test4()
{
    int x = 5;
    string category = x switch
    {
        < 0 => "Négatif",
        0 => "Zéro",
        > 0 and < 10 => "Petit positif",
        >= 10 => "Grand positif" //,
        // _ => "Inconnu"
    };
    Console.WriteLine(category);
}
    

// Tuple patterns
public static void test5()
{
    (int a, int b) pair = (1, 2);

    string res = pair switch
    {
        (0, 0) => "Origine",
        (1, _) => "X=1",
        (_, 2) => "Y=2",
        _ => "Autre"
    };
    Console.WriteLine(res);
}
    

// Property patterns
public static void test6()
{
    var person = new { Name = "Jacques", Age = 42 };
    string desc = person switch
    {
        { Age: < 18 } => "Mineur",
        { Age: >= 18 and < 65 } => "Adulte",
        { Age: >= 65 } => "Senior",
        _ => "Inconnu"
    };
    Console.WriteLine(desc);
}
    

public enum Direction
{
    Up,
    Down,
    Right,
    Left
}

public enum Orientation
{
    North,
    South,
    East,
    West
}

public static Orientation ToOrientation(Direction direction) => direction switch
{
    Direction.Up => Orientation.North,
    Direction.Right => Orientation.East,
    Direction.Down => Orientation.South,
    Direction.Left => Orientation.West,
    _ => throw new ArgumentOutOfRangeException(nameof(direction), $"Not expected direction value: {direction}"),
};

public static void test7()
{
    var direction = Direction.Right;
    Console.WriteLine($"Map view direction is {direction}");
    Console.WriteLine($"Cardinal orientation is {ToOrientation(direction)}");
    // Output:
    // Map view direction is Right
    // Cardinal orientation is East
}
    

public readonly struct Point{
    public Point(int x, int y) => (X, Y) = (x, y);

    public int X { get; }
    public int Y { get; }
}

static Point Transform(Point point) => point switch
{
    { X: 0, Y: 0 } => new Point(0, 0),
    { X: int x1, Y: int y1 } when x1 < y1 => new Point(x1 + y1, y1),
    { X: var x, Y: var y } when x > y => new Point(x - y, y),
    { X: var x, Y: var y } => new Point(2 * x, 2 * y),
};

public static void test8()
{
    Point pin = new Point(0, 1);
    Point pout = Transform(pin);
    Console.WriteLine($"point: {pout.X} {pout.Y}");
}