31-12-2010
Inheritance: Deriving the features from one class to another class can be called as inheritance.
Inheriting the base class members to derived class or inheriting the super class members into subclass pr inheriting the parent class members into child class can be called as inheritance.
To implement inheritance we will use colon ( : ) operator.
Syntax for inheritance:
<Accessmodifier> class <baseclassname>
{
// class members
}
<Accessmodifier> class <Derivedclassname> : <baseclassname>
{
// class members
}
When we will implement the inheritance all the base calss members will be logically inheriting to derived class.
Because of the inheritance derived class object can access the base calss members.
In inheritance can be classified into various types.
1. Single Inheritance: Inheriting form one base class to one derived class can be called as single inheritance.
Eg:
Class C1
{
}
Class C2:C1
{
}
Eg For single Inheritance:
namespace singleinheritanceexample
{
Public bc
{
Public int a = 10;
Public int b = 20;
Public void bc method()
{
Console.WriteLine("bc method is calling");
}
}
Public class dc:bc
{
Public int c = 30;
Public void dcmethod()
{
Console.WriteLine("dc method is calling");
}
}
Class mainclass
{
Void main()
{
dc d = new dc();
Console.WriteLine("a value is {0}, b value is {1}", d.a, d.b);
d.bcmethod();
Console.WriteLine("C value is " +d.c);
d.dcmethod();
Console.ReadLine();
}
}
}
Output: a value is 10, b value is 20
bc method is calling
c value is 30
dc method is calling
2. Multilevel Inheritance: Inheriting from one class to another class from that class to some other class can be called as multilevel inheritance
Eg:
Class C1 Class GF
{ {
} }
Class C2:C1 Clas Father:GF
{ {
} }
Class C3:C2 Class Child:Father
{ {
} }
Eg: For Multilevel inheritance:
namespace multipleinheritanceexample
{
Public class bc
{
Public int a = 10;
Public int b = 20;
Public void bcmethod()
{
Console.WriteLine("bc method is calling");
}
}
Public class dc:bc
{
Public int c = 30;
Public void dcmethod()
{
Console.WriteLine("dc method is calling");
}
}
Public class tc:dc
{
Public void tcmethod()
{
Console.WriteLine("tcmethod is calling");
}
}
Class mainclass
{
Void main()
{
tc t = new tc();
Console.WriteLine("a value is {0}, b value is {1}", t.a, t.b);
t.bcmethod();
Console.WriteLine("C value is " +t.c);
t.dcmethod();
t.tcmethod();
Console.ReadLine();
}
}
}
Output: a value is 10, b value is 20
bc method is calling
c value is 30
dc method is calling
tc method is calling
3. Multiple Inheritance: Inheriting from multiple super classes to one derived classs can be called as multiple inheritance.
EG:
Class C1 Class Fatherbrother
{ {
} }
Class C2 Clas Father
{ {
} }
Class C3:C1,C2 Class Child:Father,Fatherbrother
{ {
} }
In C#.NET by using classes we cannot implement multiple inheritance, we can achieve multiple inheritance by using interfaces.
Sealed Class: While declaring class it used sealed keyword the class can be called as sealed class.
Sealed classes cannot be inherited.
Whenever we want to restrict a class to be inherited we can declare that class as a sealed class.
Eg: For Sealed Class:
Public sealed Class bc
{
}
Public class dc:bc
{
}
The above code will generate an error because we cannot inherit scaled classes.
