Summary Classes and objects

ELITE TUTORING




C++ Classes and Objects
In previous topics, we learned about functions and variables. Sometimes it's
desirable to put related functions and data in one place so that it's logical and
easier to work with.

Suppose, we need to store the length, breadth, and height of a rectangular
room and calculate its area and volume.

To handle this task, we can create three variables, say, length , breadth ,

and height along with the functions calculateArea() and calculateVolume() .

However, in C++, rather than creating separate variables and functions, we
can also wrap these related data and functions in a single place (by
creating objects). This programming paradigm is known as object-oriented
programming.


But before we can create objects and use them in C++, we first need to learn
about classes.




C++ Class
A class is a blueprint for the object.


We can think of a class as a sketch (prototype) of a house. It contains all the
details about the floors, doors, windows, etc. Based on these descriptions we
build the house. House is the object.
Create a Class

, ELITE TUTORING



A class is defined in C++ using keyword class followed by the name of the
class.
The body of the class is defined inside the curly brackets and terminated by a
semicolon at the end.

class className {
// some data
// some functions
};


For example,

class Room {
public:
double length;
double breadth;
double height;

double calculateArea(){
return length * breadth;
}

double calculateVolume(){
return length * breadth * height;
}

};


Here, we defined a class named Room .

The variables length , breadth , and height declared inside the class are known
as data members. And, the
functions calculateArea() and calculateVolume() are known as member
functions of a class.