#include <iostream>
using namespace std;

// A class CRectArea with a constructor and descructor
// to determine the area of a rectangle.
class CRectArea {
int *width, *height;
public:
CRectArea (int,int);
~CRectArea ();
int areaofrect () {
return (*width * *height);
}
};

// Constructor
CRectArea::CRectArea (int x, int y) {

//Dynamically allocate some memory
width = new int;
height = new int;

*width = x;
*height = y;
}

// Destructor
CRectArea::~CRectArea () {
//Delete the allocate memory
delete width;
delete height;
}

int main () {
CRectArea myrectangle (2,2);
cout << “The area of the rectangle is: ” << myrectangle.areaofrect() << endl;
return 0;
}

In this example we want to determine the area of a rectangle. We use a constructor, where we dynamically allocate some memory for the width and height. In the destructor we delete the memory, we dynamically allocated in the constructor. Now, every time an instance of a class is created the constructor method is called (in this case: CRectArea myrectangle (2,2); The destructor is called near the end of the program.

Where are destructors commonly used for? They are usually used to “clean up” when an object is no longer necessary, to “clean up” the mess you have create during a program.
Hope this helps, good luck!