Class and Objects

  §  Class is a blueprint of an object

For example;

When a building is made, firstly we prepared a map for that building, which show how the building is showing in future.

But the map is not a building.

OBJECT:

It is a big memory of the block which contains multiple variables.

Variable is a block of containing single data.

  §  When you define a class you will make a new data type.

  §  This new data type is called non-primitive data type

  §  Class is a description of an object’s property set and set of operations.

      The variable contains a single value but,

      The object contains the multiple values means contains a full records 

  §  Which type of values object will contain, define in class.

  §  In class, we also define total no of variables and their size.

  §  Class have also functions which used the variables of objects.

  §  Creating a class is similar to creating a structure in C language.

  §  Class is a means to achieve encapsulation.

Encapsulation means making a single group of functions, properties to a related item.

  §  Object is a run time entity

  §  Object takes memory but, the class doesn’t take.

  §  Class is only the description of objects.

  §  Memory of object depends on the object’s variables in it.

Format of Class

  §  Here the box is the new data type.

  §  box b1 ;

        Here the box is the data type, b1 is the object.

  §  Nature of object b1 and how many memory it will consume all the details are defined in a class of that object.

  §  box b1;

  §  box b2;

  §  box b3;

  §  Here l, b, h of b1, b2 and b3 are different from each other.

   Example 1

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

class demo
{
int a,b,sum;   //data members
public:         // access specifiers

void getdata()    //memeber functions
{
  cout<<"Enter the First Number : ";
  cin>>a;
  cout<<"Enter the second number : ";
  cin>>b;
}
void display()
{
   sum=a+b;
   cout<<"Result : "<<sum<<endl;
}

 };

void main()
{
 clrscr();

 demo d,d1;
 d.getdata();
 d.display();
 d1.getdata();
 d1.display();

 getch();

Example 2

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

class demo
{
int a,b,c;   //data members
public:         // access specifiers

void input()    //memeber functions
{
  cout<<"Enter the First Number : ";
  cin>>a;
  cout<<"Enter the second number : ";
  cin>>b;
}
void multiply()
{
   c=a*b;
}

void show()
{

cout<<"Multiplication : "<<c;
}

 };

void main()
{
 clrscr();

 demo d;
 d.input();
 d.multiply();
 d.show();

 getch();
}

Example 3

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

class volume
{
int l,b,h,v;   //data members
public:         // access specifiers

void input()    //memeber functions
{
  cout<<"Enter Length : ";
  cin>>l;
  cout<<"Enter breadth : ";
  cin>>b;
  cout<<"Enter height : ";
  cin>>h;
}
void vol()
{
   v=l*b*h;
}

void display()
{
cout<<"\nEntered Details :\n";
cout<<"length : "<<l<<endl;
cout<<"Breadth :"<<b<<endl;
cout<<"Height : "<<h<<endl;
cout<<"Volumn : "<<v<<endl;
}

 };

void main()
{
 clrscr();

 volume v,v1;
 v.input();
 v.vol();
 v.display();
 v1.input();
 v1.vol();
 v1.display();

 getch();

}

}

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