Destructors

Destructors

Purpose:

The destructor is called when the object is destroyed.

The object can be destroyed automatically when the scope of the objects end (i.e. when the function ends) or explicitly by using operator delete.

The destructor must have the same name as the class, but preceded with a tilde sign (~) and it must also return no value.

We normally use the destructor when the object assigns the dynamic memory in its lifetime.

C++ Program

#include<iostream>

using namespace std;

class image

{

private:

   int *height,*width;

public:

   image(int,int);//constructor

   ~image()://destructor

   int area();//regular function

};

image::image(int x, int y)

{

   height=new int;//assigns memory dynamically using 'new'

   width=new int;

   *height=x;

   *width=y;

}

image::~image()

{

   delete height;//destroys the memory using 'delete'

   delete width;

}

int image::area()

{

   return (*height* *width);

}

void main()

{

   image obj1(10,20);

   cout<<"The area is :"<<obj1.area() <<endl;

   getch();

}

Output

The area is 200

Review Questions

1. Explain the importance of constructors and destructors with examples.

2. Write short notes on the following: Constructors and destructors.

3. Write a short note on destructor."