What and When and Where and How—ABSTRACT CLASS
What is abstract Class?
·
The main purpose of an abstract class
is to provide basic or default functionality as well as common functionality
that multiple derived classes can share and override.
·
Abstract classes are mostly used as a
partially implementation (mind it abstract class and abstract methods are
different)
·
Inside abstract class will able to declare
normal method as well as abstract method but the abstract method does not have
a definition
·
So implementation class must
implement the abstract method that is override the abstract method from the
abstract class.
·
An abstract class cannot be a sealed
class because the sealed modifier prevents a class from being inherited and the
abstract modifier requires a class to be inherited.
·
Abstract classes can have a
constructor and destructor but does not support private access specifier.
·
We are also archiving the
polymorphism via abstract class method.
·
Ex: once you create abstract methods
in abstract class. Wherever you want you can able to implement the abstract
class abstract method then add your own functionality based on the classes need.
So multiple classes can have the same name of abstract method implementation
with different functionality according to the class level. That is called
runtime polymorphism
·
Then both abstract and virtual method
is override in derived class then what is the different of abstract and virtual
method?
|
Abstract-Method
|
Virtual-Method
|
|
When you consuming the abstract
class then An Abstract method must be override in child classes
|
Virtual method is not compulsory to
override.
|
|
An abstract method doesn't have
implementation detail
|
But an virtual method have an
implementation details
|
|
Only abstract class can have
abstract method
|
But any classes can have a virtual
method
|
When and where will go for abstract class/Interface?
While getting a requirement from the client
.you feel the most of the functionality same only and small, small things we
need to add based on the requirement. that time you will go for Abstract class
that is partially implementation
A good abstract class will reduce the amount
of code that has to be rewritten because it's functionality or state can be
shared.
But there is not much more the common
functionality. At that time you will go with interface.
How to implement
·
See the below complete example of
abstract class implementation for yours better understanding
using System;
using
System.Collections.Generic;
using System.Linq;
using System.Text;
namespace
AbstractClass_Implementaton
{
//abstract
class creation
public
abstract class employee
{
protected int empid;
protected string empname;
protected double salary;
//constructor creation
public employee(int empid, string empname, double
salary)
{
this.empid = empid;
this.empname = empname;
this.salary = salary;
}
//virtual method creation
public virtual void display()
{
Console.WriteLine("Empid"
+ empid);
Console.WriteLine("EmpName"
+ empname);
Console.WriteLine("EmpSalary"
+ salary);
}
//abstract method creation
public abstract void calculatesalary(int
days);
}
//create
a derived classes for inherit a abstract classes
class
Indian : employee
{
protected
int countrycode;
//sendind a argument to the abstract class constructor using the base
keyword
public
Indian(int empid, string
empname, double salary, int countrycode) : base(empid,
empname, salary)
{
this.countrycode = countrycode;
}
//virtuakl class implementation
public override void display()
{
base.display();
Console.WriteLine("Country
Code" + countrycode );
}
//abstract
class implementation
public override void calculatesalary(int
days)
{
double
grosssal = days * salary ;
Console.WriteLine("salary
of the month" + grosssal);
}
}
class
China : employee
{
protected string state;
public China(int emid, string empname, double
salary, string state) : base(emid,
empname, salary)
{
this.state = state;
}
public override void display()
{
base.display();
Console.WriteLine("state"
+ state);
}
public override void calculatesalary(int
days)
{
double grosssal = days * salary / 20;
Console.WriteLine("slary
of the month" + grosssal);
}
}
class
europe:employee
{
protected string countryname;
public europe(int empid, string empname, double
salary, string countryname) : base(empid, empname, salary)
{
this.countryname = countryname;
}
public override void display()
{
base.display();
Console.WriteLine("countryname"
+ countryname);
}
public override void calculatesalary(int
days)
{
double grosssal = 4500 * days / 20;
Console.WriteLine("salary
of the month:" + salary);
}
}
class
Program
{
static void Main(string[] args)
{
employee e;
Console.WriteLine("Please
enter the value 1-4");
int ch =Convert.ToInt32(Console.ReadLine());
switch (ch)
{
case 1:
Console.WriteLine("*************************************************************");
e = new Indian (12, "anand", 200.33, 110);
//call the virtual method
e.display();
//call the abstract method
e.calculatesalary(30);
Console.WriteLine("*************************************************************");
break;
case 2:
Console.WriteLine("*************************************************************");
e = new China (33, "Anitha", 445.4, "sangmang");
e.display();
e.calculatesalary(30);
Console.WriteLine("*************************************************************");
break;
case 3:
Console.WriteLine("*************************************************************");
e = new europe(33, "Arun", 445.4, "Norway");
e.display();
e.calculatesalary(30);
Console.WriteLine("*************************************************************");
break;
case 4:
System.Threading.Thread.CurrentThread.Abort();
break ;
}
Console.ReadLine();
}
}
}
Thanks to All!
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