C# · Easy

Lesson 1 · On the house

Lambdas and delegates

Func, Action, Predicate, lambda syntax, and passing behavior as values.

Lesson 2

LINQ basics

Where, Select, OrderBy, First, Sum, Any, and deferred execution.

Lesson 3

Dictionary and HashSet

Key-value lookup, TryGetValue, counting, and set operations.

Lesson 4

Inheritance and polymorphism

Base classes, virtual and override, abstract members, and base calls.

Lesson 5

Interfaces

Declaring and implementing interfaces, multiple interfaces, and default methods.

Lesson 6

Records

record and record struct, value equality, with-expressions, and deconstruction.

Lesson 7

Structs and value semantics

struct vs class, copying on assignment, boxing, and readonly struct.

Lesson 8

Enums and pattern matching

enum declarations, switch on enums, is patterns, and property patterns.

Lesson 9

Generics

Generic methods and classes, type constraints, and default(T).

Lesson 10

Files and paths

File.ReadAllLines, WriteAllText, Path.Combine, and streaming with StreamReader.