polymorphism
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The document discusses polymorphism in object-oriented programming. It defines polymorphism as the ability for objects of different classes related by inheritance to respond differently to the same function call. Polymorphism can be achieved through virtual functions and allows late/dynamic binding at runtime based on the actual object type. The document also discusses early/static binding at compile time, pure virtual functions that define abstract base classes, and concrete derived classes that implement pure virtual functions from the base class.
![Simple program to access member
of class;
void show()
{
#include<iostream.h>
#include<conio.h>
cout<<"Your name is "<<name;
class data
cout<<"Your age is "<<age;
}
{
private:
};
main()
char name[12];
{
int age;
public:
void input(){
cout<<"Entr your name“;
cin>>name;
cout<<"Enter your age"; cin>>age;}
data obj,*j;
j=&obj;
j->input();
j->show();
getch();
}
5](https://image.slidesharecdn.com/polymorpisum-140106223024-phpapp01/85/polymorphism-5-320.jpg)
polymorphism
- 2. What is Meant By Polymorphism? It is a Greek word. Poly mean many. Morphism mean forms. In programing Polymorphism is the ability for objects of different classes related by inheritance to response differently to the same function call. 2
- 3. What is Polymorphism in OOP? After the inheritance it is another most important feature of OOP. In polymorphism, the member functions with same name are define in base class and also in each derived class. Polymorphism is use to keep the interface of base class to its derived classes. Polymorphism can be achieved by mean of virtual functions. In polymorphism one pointer to a base class object may also point any object of its derived class. 3
- 4. How can we access the member of class? The member of a class can be access through pointer to the class. General syntax; P -> member class; P is pointer to object. -> is member access operator. Member class. It is the member of the object; 4
- 5. Simple program to access member of class; void show() { #include<iostream.h> #include<conio.h> cout<<"Your name is "<<name; class data cout<<"Your age is "<<age; } { private: }; main() char name[12]; { int age; public: void input(){ cout<<"Entr your name“; cin>>name; cout<<"Enter your age"; cin>>age;} data obj,*j; j=&obj; j->input(); j->show(); getch(); } 5
- 7. Early Binding The Events That Takes Place At Compile Time Is Called Early Binding. Also Called Static Binding. Information Required To Call A Function Is Known At Compile Time. 7
- 8. Early Binding Example #include<iostream.h> 8 class C: public A{ public: #include<conio.h> void show() class A { cout<<"This Is Second Derived Class "<<endl; } }; public: void main() { void show() { cout<<"This Is Base Class "<<endl; } }; A *ptr; B C class B: public A C1; C2; ptr=&C1; { ptr->show(); public: void show() ptr=&C2; { cout<<"This Is First Derived Class "<<endl; } { ptr->show();
- 9. Virtual Function Special Type Function. Can Be Define In Both Derived And Base Class. Its Name Will Be Same In Every Class. Definition May Be Different. In Derived Classes It Will Be Executed Through Pointer Of Its Base Class. It is Declared By Keyword Virtual. A Redefined Function Is Said To Override The Base Class Function. 9
- 10. Late Binding The Events That Takes Place In Execution Time Is Called Late Binding. In Late Binding At The Compile Time Compiler Does Not Know Which Message Should Compiler Will Respond Because The Type Of Pointer Is Unknown At Compile Time. It Depending Upon The Contents In Pointer During Execution Time Of Program. 10
- 11. Late Binding Example 11 class C: public A{ #include<iostream.h> public: #include<conio.h> void show() class A { void main() { virtual void show() { cout<<"This Is Base Class "<<endl; A *ptr; } B }; C class B: public A C2; ptr->show(); public: ptr=&C2; { cout<<"This Is First Derived Class "<<endl; }; C1; ptr=&C1; { void show() cout<<"This Is Second Derived Class "<<endl; } }; public: } { ptr->show(); getch(); }
- 12. Pure Virtual Function The virtual function that is only declare But Not Define In The In The Base Class. General Syntax: virtual function_name()=0; The class that contains the pure virtual function exists only to act as base or parent classes. 12
- 13. Abstract Base Class The base class that has one or more pure virtual function is called the abstract base class. These classes designed as a framework or layout for derived classes An abstract base class cannot be instantiated i.e. An object of its type cannot be defined but a pointer to an abstract base class can be defined. 13
- 14. Concrete Derived Class The derived class that does not have any pure virtual function is called concrete derived class. The pure virtual function of the abstract base class is implemented in the concrete derived class. The derived classes usually have their own versions of the virtual functions 14