Difference Between Structure and Class

The most important feature of C++ is the 'class'. A class is an extension of the idea of structures used in C-language. It is a new way of creating and implementing a user-defined data type. C++ Classes is similar to structures in C-language, but with the major difference:

Difference Between Structure and Class
S.No.	Structure	Class
	By default members of the structure is public	By default members of the class is private
	All data declared in structure is public, do not permit data hiding.	Data declared in classes can be private, protected or public. Data hiding is possible.
	We cannot add 2 objects eg: object3=object1+object2 is invalid.	Addition of 2 objects is possible, eg. object3=object1+object2 is valid.

C++ Class Declaration

Class is a user-defined data type, use for wrapping different types of data and functions together. C++ Class declaration syntax:

class class_name
{
    private:
        variable declaration;
        function declaration;
    public:
        variable declaration;
        function declaration;
};

C++ Class - Example

Example 1: WAP to input student rollno, name and display it using class.

#include<iostream.h>
#include<conio.h>

class student
{
    private:
        //variable declaration
        int rollno;
        char name[20];
    public:
        //function declaration
        void input();
        void output();
};
//function definition 
void student::input()
{
    cout<<"Enter Student rollno";
    cin>>rollno;
    cout<<"Enter Student Name";
    cin>>name;
}
void student::output()
{
    cout<<"Student name is : "<<name<<endl;
    cout<<"Student rollno is : "<<rollno;
}
void main()
{
    clrscr();
    student s;  //object created
    s.input();  //calling class function input
    s.output(); //calling class function output
    getch();
}