A Class is a User Defined Data Type. It may contain functions, variables or other pre-defined data types. Classes basically encapsulate the data and methods. The syntax to declare a class is
class Test { };
A class must be ended with a semicolon.
Objects in C++:- The variables of data type Class are called objects. The objects of a particular class can access the variables and member functions of that class. Objects are declared similarly as normal variables.
datatype variable; ClassName ObjectName;
A class can have multiple objects. Every object has different copies of the variables but a single copy is shared between the objects in case of functions.
A Simple program to illustrate the uses of classes and objects-
#include<iostream.h> #include<conoi.h> class Book { private: char name[15], author[15]; int rack; public: void input() { cout<<”Enter the name of the book”; cin>>name; cout<<”Enter the author’s name”; cin>>author; cout<<”Enter the rack number to store the book”; cin>>rack; } void out() { cout<<”The book “<<name<<” by “<<author<< “is stored in rack number “<<rack; } }; void main() { Book one; one.input();//the private variables are being used outside the class BUT WITH THE HELP OF PUBLIC MEMBER FUNCTION one.out(); getch(); }