Abstraction in C++ Abstraction is the concept of exposing only the required essential characteristics and behavior

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Clinton Simmons
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Abstraction in C++ Abstraction is the concept of exposing only the required essential characteristics and behavior with respect to a context. Hiding of data is known as data abstraction.

1 Abstraction in C++ Abstraction is the concept of exposing only the required essential characteristics and behavior with respect to a context. Hiding of data is known as data abstraction. In object oriented programming language this is implemented automatically while writing the code in the form of class and object. Real life example of Abstraction Abstraction shows only important things to the user and hides the internal details for example when we ride a bick, we only know about how to ride bick but can not know about how it work? and also we do not know internal functionality of bick. Example of Abstraction in C++ #include<iostream.h> class sum // hidden data from outside world private: int a,b,c;

2 public: void add() cout<<"enter any two numbers: "; cin>>a>>b; c=a+b; cout<<"sum: "<<c; ; sum s; s.add(); getch(); Output Enter any two number: 4 5 Sum: 9

3 Encapsulation in C++ Encapsulation is a process of wrapping of data and methods in a single unit. It is achieved in C++ language by class concept. Combining of state and behavior in a single container is known as encapsulation. In C++ language encapsulation can be achieve using class keyword, state represents declaration of variables on attributes and behavior represents operations in terms of method. Advantage of Encapsulation The main advantage of using of encapsulation is to secure the data from other methods, when we make a data private then these data only use within the class, but these data not accessible outside the class. Real Life Example of Encapsulation in C++ The common example of encapsulation is Capsule. In capsule all medicine are encapsulated in side capsule. Benefits of encapsulation Provides abstraction between an object and its clients. Protects an object from unwanted access by clients. Example: A bank application forbids a client to change an Account's balance.

4 Example of Encapsulation in C++ #include<iostream.h> class sum private: int a,b,c; public: void add() cout<<"enter any two numbers: "; cin>>a>>b; c=a+b; cout<<"sum: "<<c; ; sum s; s.add(); getch(); Output Enter any two number: 4 5 Sum: 9 In above example all data and function are bind inside class sum. Object Oriented Programming has a special feature called data abstraction. Data abstraction allows ignoring the details of how a data type is represented. While defining a class, both

5 member data and member functions are described. However while using an object (that is an instance of a class) the built in data types and the members in the class are ignored. This is known as data abstraction. This can be seen from the above example. Example An example to show how public member data and public member functions are accessed outside the class. #include <iostream.h> class base ; public: int sl,s2; public: void inp_val() cout<<"input the values of sl and s2 "; cin>>sl>>s2; void disp() cout<<sl <<" "<<s2; cout<<"\n" ; base o1; o1.inp_val();

6 o1.disp(); The first occurrence of the keyword public (or private) before a member data or a member function makes the compiler assume the types of accesses of all the members following this to be of the first occurrence type. However, if the types of accesses of member data and member functions are different, then the access type should be explicitly mentioned in each case. Example An example to show that private member data cannot be accessed outside the class if the member functions which involve this data are also private. #include <iostream.h> class base private: int sl,s2; void inp_val() cout<<"input the values of s1 and s2 "; cin>>sl>>s2; void disp() cout<<sl <<" "<<s2; cout<<"\n" ;

7 ; base o1; o1.inp_val(); o1.disp(); On the execution of the above program, following error messages will appear. error messages Error oop22.cpp 26 : 'base::inp-val()' is not accessible error oop22.cpp 27: 'base::disp() ' is not accessible Example Modified version of Example in which member data are private but the member function which invoke the private data members are public. This will not cause any error as in example #include <iostream.h> class base private: int sl,s2; public: void inp_val() cout<<"input the values of sl and s2 "; cin>>sl>>s2;

8 void disp() cout<<sl <<" "<<s2<<"\n "; ; base o1; o1.inp_val(); o1.disp();

ENCAPSULATION. private, public, scope and visibility rules. packages and package level access.

ENCAPSULATION. private, public, scope and visibility rules. packages and package level access. ENCAPSULATION private, public, scope and visibility rules. packages and package level access. Q. Explain the term Encapsulation with an example? Ans: The wrapping up to data and methods into a single units