Explain the Types of Polymorphism

3.2.4. Implications of Polymorphic Use of Classes

Q22. What is polymorphism? Explain the types of polymorphism.
Answer: 
Polymorphism
Polymorphism is one of the important object oriented programming concept. It is a mechanism through which one operation or a function can take many forms depending upon the type of objects. Thus, a single operator.or function can be used in many ways.
Consider an example for adding two variables,

Sum = x+y

Here, x and y can be integer numbers

Sum = 2+5

or float numbers

Sum =2.5+7.5

The result of ‘Sum’ depends upon the values passed to it.

Types of Polymorphism
There are two types of polymorphism. They are,

(i) Compile time polymorphism and

(ii) Runtime polymorphism.

(i) Compile Time Polymorphism
In compile time polymorphism, the most appropriate member function is called by comparing the type and the number of argument by the compiler at compile time. It is also known as early binding / static linking / static binding.

Example

#include<iostream.h>

#include<conio.h>

class Add

{

public:

void sum(int a, int b)

{

cout<<a+b;

}

void sum(int a, int b, int c)

{

cout<<a+b+c;

}

};

void main()

{

clrscr();

Add obj;

obj.sum(10, 20);

cout<<endl;

obj.sum(10, 20, 30);

}

Output

(ii) Runtime Polymorphism
In this type of polymorphism, the most appropriate member function is called at runtime i.e., while the program is executing and the linking of function with a class occurs after compilation. Hence, it is called late binding or dynamic binding. It is implemented using virtual functions and the pointers to objects.

Example

#include<iostream.h>

#include<conio.h>

class Baseclass

{

public:

virtual void show()

{

cout<<“Base class \n”;

}

};

class Derivedclass: public Baseclass

{

public:

void show()

{

cout<<“\n Derived class \n”;

}

};

int main(void)

{

clrscr();

Baseclass *bp = new Derivedclass;

bp→show(); // RUN-TIME POLYMORPHISM

getch();

return 0;

}

Output