invalid conversion?

[ath2441]

This is my program:

#include <iostream>
using namespace std;

class Point
{
private: int x, y;
public:
   Point(int f = 0, int g = 0)
   {
      x = f;
      y = g;
   }
   int getX() const
   {
      return x;
   }
   int getY() const
   {
      return y;
   }
   void setX(const int new_x)
   {
      x = new_x;
   }
   void setY(const int new_y)
   {
      y = new_y;
   }
};
class PointArray
{
private:
   Point * loc;
   int len;
   public:
   PointArray()
   {
      len = 0;
      loc = new Point[0];
   }
   PointArray(const Point * points, const int size)
   {
      len = size;
      loc = new Point[len];
      for(int f = 0; f < len; f++)
         loc[f] = points[f];
   }
   PointArray(const PointArray& pv)
   {
      len = pv.len;
      loc = new Point[len];
      for(int f = 0; f < len; f++)
         loc[f] = pv.loc[f];
   }
   ~PointArray()
   {
      delete[] loc;
   }
   void resize(int n)
   {
      Point *loc1 = new Point[n];
      for(int f = 0; f < len && f < n; f++)
         loc1[f] = loc[f];
      len = n;
      delete[] loc;
      loc = loc1;
   }
   void pushBack(const Point &p)
   {
      resize(len+1);
      loc[len-1] = p;
   }
   void insert(const int pos, const Point &p)
   {
      resize(len+1);
      for(int f = len-1; f > pos; f--)
         loc[f] = loc[f-1];
      loc[pos] = p;
   }
   void remove(const int pos)
   {
      for(int f = pos; f < len-1; f++)
         loc[f] = loc[f+1];
      resize(len-1);
   }
   const int getSize() const
   {
      return len;
   }
   void clear()
   {
      resize(0);
   }
   Point * get(const int pos)
   {
      if (pos >= len)
         return NULL;
      else 
      {
         Point * x = new Point();
         *x = loc[pos];
         return x;
      }
   }
   const Point * get(const int pos) const
   {
      if (pos >= len)
         return NULL;
      else 
      {
         Point * x = new Point();
         *x = loc[pos];
         return x;
      }
   }
};
class Polygon
{
protected: 
   PointArray * loci; 
   int sides;
   static int N;
   public:
   Polygon(Point * loc, int len)
   {
      loci = new PointArray(loc, len);
      sides = len;
      N++;
   }
   Polygon(const PointArray& pv)
   {
      loci = new PointArray(pv);
      sides = pv.getSize();
      N++;
   }
   Polygon(const Polygon& pv)
   {
      loci = new PointArray(*pv.loci);
      sides = pv.sides;
      N++;
   } 
   ~Polygon()
   {
      delete loci;
      N--;
   }
   virtual double area() = 0;
   static int getNumPolygons()
   {
      return N;
   }
   int getNumSides()
   {
      return sides;
   }
   const PointArray * getPoints()
   {
      return loci;
   }
};
class Rectangle : public Polygon
{ 
private:
   typedef Polygon super;
   void makeRectangle(const Point e, const Point r)
   {
      Point * loci = new Point[4];
      loci[0] = e;
      loci[2] = r;
      loci[1] = new Point(e.getX(), r.getY());
      loci[3] = new Point(r.getX(), e.getY());
   }
   void makeRectangle (const int x1, const int x2, const int y1, const int y2)
   {
      Point * loci = new Point[4];
      loci[0] = new Point(x1, y1);
      loci[1] = new Point(x2, y1);
      loci[2] = new Point(x2, y2);
      loci[3] = new Point(x1, y2);
   }
};

The compiler is giving me these errors in the two overloaded makeRectangle() when they call the Point(int, int) constructor, saying:
geometry.cpp: In member function 'void Rectangle::makeRectangle(Point, Point)':
geometry.cpp:170:45: error: invalid conversion from 'Point*' to 'int' [-fpermissive]
geometry.cpp:8:4: error: initializing argument 1 of 'Point::Point(int, int)' [-fpermissive]
geometry.cpp:171:45: error: invalid conversion from 'Point*' to 'int' [-fpermissive]
geometry.cpp:8:4: error: initializing argument 1 of 'Point::Point(int, int)' [-fpermissive]
geometry.cpp: In member function 'void Rectangle::makeRectangle(int, int, int, int)':
geometry.cpp:176:33: error: invalid conversion from 'Point*' to 'int' [-fpermissive]
geometry.cpp:8:4: error: initializing argument 1 of 'Point::Point(int, int)' [-fpermissive]
geometry.cpp:177:33: error: invalid conversion from 'Point*' to 'int' [-fpermissive]
geometry.cpp:8:4: error: initializing argument 1 of 'Point::Point(int, int)' [-fpermissive]
geometry.cpp:178:33: error: invalid conversion from 'Point*' to 'int' [-fpermissive]
geometry.cpp:8:4: error: initializing argument 1 of 'Point::Point(int, int)' [-fpermissive]
geometry.cpp:179:33: error: invalid conversion from 'Point*' to 'int' [-fpermissive]
geometry.cpp:8:4: error: initializing argument 1 of 'Point::Point(int, int)' [-fpermissive]
Because x1, x2, y1, and y2 are integers and therefore should be compatible with the Point(int, int) constructor, I do not understand why it is giving me the error: "invalid conversion from 'Point*' to 'int'".

[Computergeek01]

You can't save pointers to an array of non-pointer objects. The operator "new" dynamically allocates the object and returns a pointer to it not the instance of the object itself. What are you trying to do on Line 167? Is it meant to be a pointer to an array or a pointer to an array of pointers? Either one is valid.

[ne555]

your errors seem to refer to the Point constructor. However, the problem is that you are trying to assign a pointer to an object, as clang points out:

foo.cpp:170:12: error: no viable overloaded '='
                        loci[1] = new Point(e.getX(), r.getY());
                        ~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
foo.cpp:4:7: note: candidate function (the implicit copy assignment operator) not viable: no known conversion from 'Point *' to 'const Point' for 1st argument; dereference the argument with *

the solution is not what clang proposes, but simply dropping the new
loci[1] = Point(e.getX(), r.getY());

By the way, you are leaking memory as `loci' is a local variable in `makeRectangle()', you are not referring to the member `loci'

Your `PointArray' lacks an adequate assignment operator. You should simple use std::vector

class Polygon
{
protected: 
   PointArray * loci; //¿is there a good reason to use a pointer here? 

[ath2441]

Omitting the 'new' before each of the calls to the Point(int, int) constructor resolved the error. The compiler's error message was not very clear to me because I did not see where I was trying to convert from 'Point*' to 'int'.

Thank you for helping.