Classes and Structs

In this chapter you will learn:

  1. How to create custom types

What is custom types

We can use classes and structs to build new types. Classes and structs are a data structure that encapsulates a set of data and behaviors. The data and behaviors are the members of the class or struct.

A class or struct type is like a blueprint. After class or struct type declaration we can create instances or objects at run time.

Suppose we create a class called Person and variable p is Person type, the p is said to be an object or instance of Person.

We can define multiple instances of the same Person type, for example, p1, p2, p3. p1, p2, p3 can have different values in its properties and fields.

A class is a reference type, which means p1 hold only a reference to the Person object. A struct is a value type.

In the following example, Rectangle is defined with two members. An instance (object) of Rectangle is created in the Main method, and the object's methods and properties are accessed by using dot notation.

// Class definition./*  ja  v  a 2 s. c  om*/
public class Rectangle
{
    public int Width;
    public int Height;
}

public class MainClass{
   public static void Main(){
      Rectangle r = new Rectangle();
      
      r.Width = 5;
   }

}

Next chapter...

What you will learn in the next chapter:

  1. What is Encapsulation and why it is useful
Home » C# Tutorial » Class
Classes and Structs
Encapsulation
Class and Struct Accessibility
Members
Static Members
Class
Class instance variables
Class instance Methods
Class Inheritance
Class constructor
Default constructors
Parameters of constructors
Constructor overloading
Static Constructor
Destructor
Override destructor
new operator
Class field
Static Fields
Read only field
Field default value
const value
Abstract class
Static Class
Partial type
Methods
Method local variable
Method Overloading
Method overloading with ref and out
Type conversion and method overloading
Error in Method overloading
virtual methods
Override methods
Method Parameter
Pass parameters
ref parameters
out parameters
Variable parameter length
Optional parameters
Named parameters
static method
function Return
Recursive methods
Virtual methods and polymorphism
Cast
Shadow inherited members
Seal a member
this keyword
base keyword
base and name hiding
Access Specifiers
private
public
protected
internal
Indexer
String type indexer
Multidimensional indexer
Indexer overloading
Indexer to append
Indexer logic
Properties
Properties getter and setter
Accessibilities of properties
Automatic properties
Read only and write only property
Virtual properties
Abstract Properties
Static Properties
interface
interface implementation
Explicit interface implementation
Interface inheritance
Indexer in an interface
Interface Properties
struct and interface
virtual interface implementation
as operator
is operator
null reference
Nested classes
object class
ToString method
GetHashCode
Object initialization
Extension method
Struct Instances vs. Class Instances