26. Pattern matching, tuples and deconstruction

object shape = new Circle(2);
double area = shape switch
{
    Circle { Radius: var r } => Math.PI * r * r,          // property pattern
    Rectangle(var w, var h) => w * h,                      // positional pattern
    null => throw new ArgumentNullException(nameof(shape)),
    _ => 0
};

if (order is { Status: Status.Shipped, Total: > 1000 }) { /* ... */ }
int[] arr = [1, 2, 3];
if (arr is [1, .., var last]) Console.WriteLine(last);    // list pattern (C# 11)

(string Name, int Age) GetUser() => ("Asha", 28);           // tuple
var (name, age) = GetUser();                                // deconstruction