Thread: Homework project(need help)

Hello everyone. Here is my problem.I am given four classes (Point,Shape,Circle,Rectangle)
and I must complete theme so as the program works.
Here is my project:

Code:

   //shapes.h
#ifndef shapes_h
#define shapes_h

1 class Point{
           private:
              int x;
              int y;

       public:
              Point();
              Point(int k, int l);
              ~Point();
              void setX(int );
              int getX() const;
              void setY(int );
              int getY() const;
              void print() const;
             Point & operator=(const Point &p1);
              };

 
//Abstract class
2 class Shape {
            public:
            //.....
            virtual double Area() =0;
            virtual double Perifereia() =0;
            virtual void print() const = 0;

            };
3 class Rectangle : public Shape {
             private:
             Point *myUpperLeft;
             Point *myLowerRight;
             public:
             double Area();
             void print() const;
             double Perifereia();
             int GetWidth() const; 
             int GetHeight() const; 

             Rectangle(Point *pUL, Point *pLR);
           };

4 class Circle : public Shape, public Point 
                             {
                              public:
                              // .......
                               private:
                               double radius;
                              virtual double Area() =0;
                              };
    #endif

shapes.cpp

Code:

#include <iostream>
#include <cmath>
using namespace std;
#include "shapes.h"

//Class Point Functions
Point::Point(int k,int l )
{x=k;y=l;}
Point::Point ()
{x=y=0;}
Point::~Point()
{}
void Point::setX(int xValue) {x=xValue;}
int Point::getX() const{return x;}
void Point::setY(int yValue) {y=yValue;}
int Point::getY() const{return y;}
void Point::print()const{cout<<"["<<x<<","<<y<<"]"<<endl;}

 Point & Point::operator=(const Point &p1)
 {
      if(this !=&p1)
        {
         x=p1.x;
         y=p1.y;
        }
 return *this;
 }

//Class  Rectangle functions
int Rectangle::GetWidth()const{return myUpperLeft->getX()-myLowerRight->getX();} /*line1*/

Rectangle::Rectangle(Point *pUL, Point *pLR)    //error here                 /*line2*/
{
 myUpperLeft=pUL;
 myLowerRight=pLR;
};

and main.cpp has nothing special.


I use Dev-C++ and the error message is
"[Linker error] undefined reference to 'vtable for Rectangle'"

hmm... Dev-C++? If I remember correctly there was some strange bug such that a custom class with the name "Rectangle" causes problems. You may have to change the class name, or perhaps place it in some namespace (recommendation not tested).

EDIT:
Okay, I did a test and could not duplicate the error that I had with a class named "Rectangle" some time back. It could be that I am mistaken.

Another bug in the "flawless" devC++. It would not hurt to have a back up IDE. Code::blocks is quite good as is any MS one apart from version 6.0. Bloodshed have abandoned working on DevC++. 4.992 the final version. It has a few bugs still, which were never filtered out. Most of the help files are missing or painfully incomplete too. As Laserlight pointed out.

do you have a body for Area function in Rectangle class?

Wait - Rectangle is an abstract base class itself, since you did not implement some of the virtual functions inherited from Shape. I jumped to a premature conclusion.

May I suggest a few changes? For one thing, you might want to improve your code formatting to make your code easier to read: one reason why I made my earlier assumption was that I could not be bothered to examine your code carefully in the messed up form that was displayed in my browser.

Also, Point does not need to define a copy assignment operator or a destructor as the compiler generated versions will work perfectly fine.