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C Language and .NET

Recommended Textbooks on C#:

  • C# in Depth, 4th ed., by Jon Skeet
  • Code Like a Pro in C#, by Jort Rodenburg

OOP Recap Textbook:

  • Design Patterns: Elements of Reusable Object?Oriented Software, by Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides (Gang of Four)

Why use C#​

  • We use C# in our chosen game engine Unity
  • I'm learning .NET because it's a web framework written in C# too. I think it will be easier to have our codebase in one language so that new developers have an easier time contributing.

What is C#?​

I'm following the microsoft docs

Also reading through Head First C#

  • C# is a statically typed, object oriented language.
  • Similar operation precedence to Javascript

Types in C#​

  • Value Type: Directory contain their data
    • Tuples: concise syntax to group multiple data elements in a lightweight data structure
  • Reference Type: Objects --> Store references
    • Class types: Base class of all other types object.
      • Defines data members and function members
      • Support single inheritance and polymorphism
      • Polymorphism: Can extend base class through method overriding
    • Interface types: User defined interfaces
    • Array types
    • Delegate types: represents references to methods with a particular parameter list and return type
      • Like function pointers, but OO and type-safe
  • Nullable types: 
    int? optionalInt = default;

Organizational concepts in C#​

A hierarchy of organizational concepts:

  • programs: Encapsulate namespace(s)
  • namespaces: Organize related type(s)
  • types: Contain member(s)
  • members: Any element that that makes up a type.
    • Static members: Belong to classes
    • Instance members: Belong to objects (instances of a class)
    • Members can be constants, fields, methods, properties, etc..
    • Accessibility: `[public, private, protected, internal, protected internal, private protected]
  • assemblies: Compiled output of a program or library. Typically has a .dll or .exe file extension

Methods and other function members​

  • virtual method: declared and implemented in a base class where any derived class may provide a more specific implementation
  • override method: implemented in a derived class that modifies the behavior of the base class' implementation
  • abstract method: declared in a base class that must be overridden in all derived classes
    • Virtual method with no implementation
  • Method overloading: C# allows method overloading (unique signatures / unique params for methods of the same name)

Other function members include:

  • Properties:
  • Indexers:
  • Constructors:
  • Events:
  • Finalizers:
  • Operators:
  • Expressions:
  • Statements:

Other features​

  • All collections share a unifying principle for iteration
    • All collections can be used with LINQ queries
  • LINQ queries: SQL like syntax for composing queries on collections
    • Works with Memory, XML, databases, arrays, etc.. ALL COLLECTIONS!
int[] numbers = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 };

var evenNumbers = from num in numbers
                  where num % 2 == 0
                  select num;
  • C# supports async and await

.NET Architecture

  • C# programs run on .NET (virtual execution system called the common language runtime CLR)
    • CLR is an implementation of the common language interface (CLI) --> international standard
  • C# is compiled into an intemediate language (IL) conforming to CLI
    • Intermediate language is compiled to machine code
  • Execution of a C# Program:
    • Assembly loads CLR
    • Just in time (JIT) compilation converts the IL code to native machine instructions
    • CLR executes machine instructions directly on the processor

What questions did I ask?​

  • What are generic classes used for?
  • What is the main use case of delegate types? One use case seems to be mapping functions over arrays, but what other ways can this paradigm be applied?

What sounds interesting?​