Constructors

Every class has at least one it's ownconstructort. Constructor creates a instance for the class. Constructor initiates (initialize) something related to the class's methods. Constructor is the method which name is same to the class. But there are many difference between the method (function) and the Constructor.

In this example we will see that how to to implement the constructor feature in a class. This program is using two classes. First class is another and second is the main class which name is Construct. In theConstruct class two objects (a and b) are created by using the overloaded another Constructor by passing different arguments and calculated the are of the different rectangle by passing different values for the another constructor.

class another{
  int x,y;
  another(int a, int b){
  x = a;
  y = b;
  }
  another(){
  }
  int area(){
  int ar = x*y;
  return(ar);
  }
}
public class Construct{
   public static void main(String[] args)
 {
 another b = new another();
 b.x = 2;
 b.y = 3;
 System.out.println("Area of rectangle : " + b.area());
 System.out.println("Value of y in another class : " + b.y);
 another a = new another(1,1);
 System.out.println("Area of rectangle : " + a.area());
 System.out.println("Value of x in another class : " + a.x);
 }
}

********************************************************************************


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

//using namespace std;

class Exforsys

{

    private:

int a;

    public:

Exforsys()

{ }

Exforsys(int w)

    {

a=w;

    }

    Exforsys(Exforsys& e)

    {

a=e.a;

cout << " Example of Copy Constructor\n";

    }

    void result()

    {

cout<< a;

    }

};

void main()

{
clrscr();
    Exforsys e1(50);

    Exforsys e3(e1);

    cout<< "ne3=";e3.result();
getch();
}