Objects, classes, and structures

An object is a programming structure with data, behavior, and identifier.
Object Data is contained in the fields, attributes, and events of the object. The object behavior is defined by the methods and interfaces of the object.

Objects have the following features:

• C # uses all objects, including Windows Forms and controls.

• Objects are instantiated. That is, objects are created from templates defined by classes and structures.

• Objects use properties to obtain and modify information they contain.

• Objects usually have methods and events that allow them to perform operations.

• Visual Studio provides a tool for operating objects: Use You can change the properties of an object (such as a Windows form. Use Check the object content.

• All C # objects are inherited from .

Class has the following features:

• C # only supports single inheritance: A class can only be inherited from one base class.

• A class can implement multiple interfaces.

• Class definition can be split between different source files. Partial.

• A static class is a sealing class that only contains static methods.

• The class is defined using the clsss keyword.

  Class
  Public class person
  {
  // Field
  Public string name;
  
  // Constructor
  Public Person ()
  {
  Name = "unknown ";
  }
  
  // Method
  Public void setname (string newname)
  {
  Name = newname;
  }
  }
  Class testperson
  {
  Static void main ()
  {
  Person person1 = new person ();
  System. Console. writeline (person1.name );
  
  Person1.setname ("John Smith ");
  System. Console. writeline (person1.name );
  }
  }
  
  

   

The structure has the following features:

• The structure is the value type, and the class is the reference type.

• When a structure is passed to a method, the structure is passed by passing values, rather than being passed as a reference.

• Unlike classes, the new operator can be used for structure instantiation.

• The structure can declare constructors, but they must contain parameters.

• A structure cannot inherit from another structure or class, and cannot be the base of a class. All structures are directly inherited fromSystem. valuetypeThe latter inherits fromSystem. Object.

• Structure can implement interfaces.

• It is incorrect to initialize the instance field in the structure.

• The structure is defined by the struct keyword.

• Although the static fields of the structure can be initialized, the structure instance field declaration still cannot use the Initial Value Setting item.

• The default constructor (constructor without parameters) or destructor cannot be declared in the structure.

  Structure
  Public struct coords
  {
  Public int X, Y;
  
  Public coords (INT P1, int P2)
  {
  X = p1;
  Y = P2;
  }
  }
  
  

   

StructType suitable for representationPoint,RectangleAndColorAnd Other lightweight objects. Although a vertex can be expressed as a class, the structure is more effective in some cases.