13_4.cpp

//example on constructors and destructors
#include <iostream>
using namespace std;

class CRectangle
{
      int *width, *height;
      public:
             CRectangle(int, int);
             ~CRectangle();
             int area(void)
             {
                 return (*width * *height);
             }
};

CRectangle::CRectangle(int a, int b)
{
                           width = new int;
                           height = new int;
                           *width = a;
                           *height = b;
}

CRectangle::~CRectangle()
{
                         delete width;
                         delete height;
}

int main()
{
    CRectangle rect(8,10), rectb(9,9);
    cout << "rect area: " << rect.area() << endl;
    cout << "rectb area: " << rectb.area() << endl;
    getchar();
    return 0;
}