constructors

Constructors

 constructors are the special data member of the class,

they have some special property are as follows:-

1) Same name of the class name .

2) have no return type.

3) No need to call in the main ,they get called when the object  is created.

General form of the constructor is :-

class name ()

{

body of the constructor

}

there are three types of constructor

1) default constructor

2) parameterised constructor

3)copy constructor

1) Default cons

   consider the following code

#include < iostream.h>

#include <conio.h>

class Sample

{

int num;

Sample ()        //constructor

{

cout<<"constructor called"<<num;

}

};

void main()

{

Sample ob;

getch();

} 

>>>>>>>>>>>Copy constructor<<<<<<<<<<<<<<<<

It is used to Copy one object into another

classname ( Class Name   & Object name)

{

body

}

Eg-->

class Sample

{

int i;

public:

Sample()        //default

{

i=0;

}

Sample(int a)   //parameterised

{

i=a;

}

Sample( Sample &ob)  //copy cons

{

i = ob.i;

}