Inheritance

Passing the baseclass "state" in place of state1, state2, state3 does not work as the child classes contain additionaly required variables not present in "state".

The only way of doing this that I can think of is as follows:

using System;

class Test
{
    static void Main()
    {

       child1 c1 = new child1();
       state1 s1 = (state1)c1.xyz();

       child2 c2 = new child2();
       state2 s2 = (state2)c2.xyz();

       child3 c3 = new child3();
       state3 s3 = (state3)c3.xyz();

    }

}

class common
{
    public state xyz()
    {
       state s = null;

       if (this is child1)
         s = new state1();
       else if (this is child2)
         s = new state2();
       else if (this is child3)
         s = new state3();

       return s;         
    }
}

class child1: common {}

class child2: common {}

class child3: common {}

class state
{

}

class state1 : state
{
   public state1()
   {
      Console.WriteLine("state1");
   }
}

class state2 : state
{
   public state2()
   {
      Console.WriteLine("state2");
   }
}

class state3 : state
{
   public state3()
   {
      Console.WriteLine("state3");
   }
}

/* the output is:

state1
state2
state3

*/

/* the output is:

state1
state2
state3

*/

However, it's hardly good OO practice for a base class to assume knowledge of  its child classes so I can't really recommend it unless you must do it this way for some reason.

I have a doubt in Inheritance

1,I have a common class named - common
It has 3 child classes child1,child2,child3

2, I have a common class named - state

It has 3 child classes state1, state2, state3


I have a function  named xyz() in all the  3 childclasses of common, which I want to move to the parent class common.

The  function xyz( ) in child1 uses state1 class inside the function, creates object for state1 class.

The  function xyz( ) in child2 uses state2 class and creates object for state2 class.

The  function xyz( ) in child3 uses state3 class and creates object for state3 class.

But the procedure is same in all the function xyz()of the 3 childclasses, the only difference is usage of classes state1, state2, state3.

In this case how can I  put that xyz()function in parent class.so that all the 3 child classes can access the function from the parent class...

Is it necessary that I have to use Generic Inheritance....
could anybody throw some light on it?

just create a virtual function in state called  DoStateSpecific.  Overridde it in all three state classes.

Move xyz to the child base class and declare a member in the child base class

state _state;

or you can pass the state into xyz

xyz(state myState)    // myState can be of type state1, state2, state3

do the state specific stuff inside of the DoStateSpecific override function.