C++ Classes and Objects

Class:-
-> Language supports different data type like int, float, char, long, structure etc. Similar to that C++ supports class data type.

-> A class is a user defined data type which has data members and member functions. They can be accessed through class variables (objects).

-> A class is like a Blue print for an object.

-> By default, All members in the class are Private.

For Ex:
Fruit is a class.
Then mango, orange will be objects of class.

Objects

-> Class type variable is known as object.

->  An object is an instance of a class.

-> Objects are basic runtime entities in an object oriented system.

-> In Structured programming problem is divided into function unlike this, in OOPs the problem is divided into objects.

// C++ program using class to calculate Area.

#include<iostream>

using namespace std;

class  shape

{

      private:

                      int l,b,area;

      public:

                     void input()

      {

              cout<<"Enter l and b values:";

               cin>>l>>b;

       }

void calculate()

{

         area = l*b;

}

void output()

{

        cout<<"Area is:"<<area;

}

};

int main()

{

      shape s;

      s.input();

      s.calculate();

      s.output();

      return 0;

}

OUTPUT:

Enter l and b values:6    5

Area is:30

*Abstraction using classes: An abstraction can be achieved using classes. A class is used to group all the data members and member functions into a single unit by using the access specifiers. A class has the responsibility to determine which data member is to be visible outside and which is not.

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