Classes and objects

1. Declaration of class, format:

Type
Tmyclass = class
End;

Type
Tbase = class
Procedure MSG1;
End;

Type
Tchild = class(tbase) // class inheritance
Procedure MSG2;
End;

The class can be declared in the interface section, or it can be declared in the application part; Type can be omitted if only one union is used;

Unitunit1;

Interface

Uses
Windows, Messages, sysutils, variants, Classes, Graphics, Controls, Forms,
Dialogs, Stdctrls;

Type
TForm1=Class(Tform)
End;

Type
Tbase=Class//Defining classes
  b  :  TDate;     declaring a variable of a class
Procedure MSG1; method of the//class
End;

Var
Form1:tform1;

Implementation

Procedure TBASE.MSG1; // Define Process entities
Begin
ShowMessage (' is Base ');
End;

Procedure Tform1.button1click (sender:tobject);
Var
Base:tbase; // Declare the variable of the class, that is, the object of the class;
Begin
Base:= tbase.create; // class needs to be instantiated for use;
BASE.MSG1;
Base.     Free; // release after use;
End;
End.

Classes and objects