+-----------------------------+----------------------------------------------+
| Concept | Syntax / Example |
+-----------------------------+----------------------------------------------+
| Inheritance & Override | class Dog : Animal { override Speak(); } |
| Abstract Class | abstract class Shape { abstract Area(); } |
| Interface | interface IDraw { void Draw(); } |
| Delegate | delegate int Op(int x, int y); |
| Event | public event EventHandler Clicked; |
| Func/Action | Func<int, int, int> adder = (a,b)=>a+b; |
| LINQ Filter | list.Where(x => x > 5) |
| LINQ Group/OrderBy | list.OrderBy(x => x.Name) |
| Async Method | async Task Foo() { await Bar(); } |
| Exception | throw new CustomException("Error") |
+-----------------------------+----------------------------------------------+