OOP PROGRAMMING

• C# ignores white space


  However, multiple lines makes the code more readable
• C# uses {} curly braces


  As markers of beginning and end of a chunk of code
• "using [NameOfNamespace]"


  Is used to import namespaces and use classes of it
• "namespace"


  Is used to organize codes; a container for classes and other namespaces
• C# statement


  Ends with a semicolon ;
• C# file name


  Does not have to match the class name, but they often do (for better organization)
• C# is case-sensitive


  "MyClass" and "myclass" have different meaning
• C# usually has the Main method


  Any code inside its curly brackets {} will be executed (Program entry point)
• Comments


  Multi-line and single line
• String


  Using double quotations ("") to print texts/strings
• Statement


  A single line of code that ends in a semicolon, or a series of single-line statements in a block
• Statement block


  Enclosed in {} brackets and can contain nested blocks
• Declaration statement

  Introduces a new variable or constant. A variable declaration can optionally assign a value to the variable. In a constant declaration, the assignment is required.
• Constant


  Immutable values which are known at compile time and do not change for the life of the program. Declared with the const modifier.
• Expression statement


  Expression statements that calculate a value must store the value in a variable. Assignment, method invocation, new object creation.
• Method


  A set of instructions grouped together within a code block. When a program needs to carry out these instructions, it calls the method and provides any necessary arguments.
• Main method


  The starting point for any C# program, initiated by the common language runtime (CLR) upon program launch.
• Method declaration


  • Access level (e.g. public, private)
  • Optional modifiers (e.g. abstract, sealed)
  • Return value
  • Name
  • Method parameters
• Method signature


  The parts of a method declaration that together define the method
• Calling a method


  • Motorcycle.MethodName()
• Method parameters vs arguments

  Parameters are the names and types defined in the method declaration, arguments are the concrete values provided when calling the method
• Passing by reference vs value

  Value types are passed by copy, reference types are passed by reference. Use the ref keyword to pass value types by reference.
• Return values


  Methods can return values to the caller, either by value or by reference using the return statement. The return statement also stops method execution.
• Custom methods


  User-defined methods that contain a specific set of code instructions, declared within a class or struct. Can be used to organize code, reuse code, and define custom business logic.
• Method overloading


  Defining multiple methods with the same name but different parameter lists within the same class
• Arrays


  • Single-dimensional
  • Multi-dimensional
  • Jagged
• Single-dimensional array


  A sequence of like elements accessed by index
• Multi-dimensional array


  Arrays with more than one dimension
• Jagged array


  An array of arrays, possibly of different sizes
• ArrayList


  • Stores elements of multiple data types whose size can be changed dynamically
• Linked list


  • A linear data structure where each element (node) contains data and a reference to the next node
• Access modifiers


  public: accessible for all classes

  private: only accessible within the same class

  protected: accessible within the same class or inherited classes

  internal: only accessible within the same assembly
• private access modifier


  • A private field can only be accessed within the same class