C / C++ / MFC

//inherit/geogroup.hpp

#ifndef GEOGROUP_HPP
#define GEOGROUP_HPP

//include header file for the base class
#include "geo.hpp"

//header for the internal management of the elements
#include <vector>

namespace Geo
{
	/*class GeoGroup
	 *	-derived from GeoObj
	 *	-a GeoGroup Consists of
	 *		-A reference point (inherited)
	 *		-A collection of geometric elements (new)
	 */
	Class GeoGroup : public GeoObj
	{
	protected:
		std::vector<GeoObj*> elems;		//collection of pointers to GeoObjs

	public:
		//constructor with optional reference point
		GeoGroup(const Coord& p = Coord(0,0)) : GeoObj(p)
		{
		}

		//output (now also implemented)
		virtual void draw() const;

		//insert element
		virtual void add(GeoObj&);

		//remove element
		virtual bool remove(GeoObj&);

		//virtual destructor
		virtual ~GeoGroup()
		{
		}
	};

}//*****END namespace GeoGroup*****

#endif		//GEOGROUP_HPP

//inherit/geogroup.cpp

//include header class
#include "geogroup.hpp"

//header for algorithms
#include <algorithm>

namespace Geo
{
	/*add
	 *	-insert elements
	 */
	void GeoGroup::draw() const
	{
		for (unsigned i = 0 ; i < elems.size(); ++i)
		{
			elems[i]->move(refpoint);		//add offset for the reference point
			elems[i]->draw();				//draw element
			elems[i]->move(-refpoint);		//subtract offset
		}
	}

	/*remove
	 *	- delete element
	 */
	bool GeoGroup::remove(GeoObj& obj)
	{
		//find first element with this address and remove it
		//return whether an object was found and removed
		std::vector<GeoObj*>::iterator pos;
		pos = std::find(elems.begin(), elems.end(), &obj);
		if (pos != elems.end())
		{
			elems.erase(pos);
			return true;
		}
		else
		{
			return false;
		}
	}
}