Scenario-
Abstract class without abstract members.
Function present in both base class and child class. This concept is called Method hiding.

    public class MyClass
    {
        public void foo()
        {
            Console.WriteLine("Base version of foo");
        }
    }

    public class MyChild : MyClass
    {
        public new void foo()
        {
            Console.WriteLine("Child version of foo");
        }
    }

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Scenario :- Function present in base class not present in child class.

    public class MyClass
    {
        public void foo()
        {
            Console.WriteLine("Base version of foo");
        }
    }
    public class MyChild : MyClass
    {

    }

We will create objects of base and child normally 
and through casting in following samples:-

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Polymorphism means one thing exists in many forms of its own with each form having different implementation of its own.
Polymorphism can be compile time or run-time.

Compile time polymorphism includes:-
1.) Function Overloading
2.) Operator Overloading

Function Overloading:-
   Function overloading depends on:-
1.) Variable Number of parameters to function
2.) Order of parameters to function
3.) Data type of parameters
Function overloading doesn’t depend on:-
1.) Return type of function
2.) Name of parameters Continue reading →

Now we will consider cases on which function overloading depends on:-

3. Variable Number of parameters to function

  public class MyBaseClass
    {
        public void foo()
        {
            Console.WriteLine("Hi I am original");
        }
        public void foo(int i)
        {
            Console.WriteLine("Hi I am overloaded and 
 here is the value of i " + i.ToString());
        }
    }

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6.) Overloading in case of inheritance

public class MyBaseClass
    {
        public void foo(int i)
        {
            Console.WriteLine("The is one parameter function which takes 
int as parameter and value of i is {0}.", i);
        }
    }

    public class MyChildClass : MyBaseClass
    {
        public void foo(string s)
        {
            Console.WriteLine("The is one parameter function which takes 
string as parameter and value of s is {0}.", s);
        }
    }

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Scenario:-
Function declared as virtual in base class and overridden in child class. See the sample code below:

  public class MyClass
    {
        public virtual void foo()
        {
            Console.WriteLine("Base version of foo");
        }
    }

    public class MyChild : MyClass
    {
        public override void foo()
        {
            Console.WriteLine("Child version of foo");
        }

    }

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Inheritance:-

Inheritance basically provides two models. Reusability model and extensibility model. Reusability model was there in C also through header file and in VB since Visual Basic is an object based language. An object based language is the one where in we can use the objects or components or modules as is but can’t modify or extend their behavior.
Interview Definition: – Extending or enhancing the functionality of base class.
In inheritance few terms or concepts that needs mentioning are hiding and overriding.
Method or Data Hiding: – Having data member or function in child class having same signature as that in base class. This is not an error but compiler shows you a warning messages when you have same data member in both child and base stating that you are hiding the base class implementation if hiding is intended use new keyword. So by specifying new keyword with data member and functions you can hide base class’s implementation of data or function. This will be clearer with an example later on. Continue reading →

Introduction

OOPS or Object Oriented Programming Concepts but some of the concepts have been always used in one or the other programming languages. For example you must have used structs in C which is a good example of encapsulation. There are four major pillar of OOPS. Let’s try to understand each one of them by taking some examples also:-
1.) Encapsulation
2.) Abstraction
3.) Polymorphism
4.) Inheritance

Encapsulation:-

Interview Definition: – Binding data and member functions together inside a single unit.
How to Encapsulate:- By creating types e.g. Classes and Struct
Bu using encapsulation we can create our own custom types by reusing the existing or primitive types. Continue reading →