User defined data type which contains data and methods to manipulate that data; is known as class. It is the fundamental packaging unit of OO technology. An object is a variable of a Class. Each object is associated with the data of type class with which it is created. Thus we can also say that class is a collection of objects of similar types. It is a user defined data type and behaves like built-in data type of the language. Since class has data and methods to manipulate the data, it supports one of the most important features of OO: Data Encapsulation.

Eg.

class Student

{

int rollno;

int marks1, marks2;

public:

void show(int r); // to print marks

void sum(int r); // to add the marks

};

We can create objects of class using:

class Student s1, s2;