Thread: Some questions regarding DLL's

Basically, I have to make a GUI that interacts with the user and based on things like the coordinates of the points where the user clicks, stores certain values in a set of data types defined by me. The datatypes have been defined in a seperate file in c++ style, ie, using classes. However I really dont want to implement the GUI using C++. Agree or not, C++ sucks at making GUI's. I prefer using VB. So what I thought was, to make a DLL of the user defined data types and then use the dll in VB. Unfortunately I am a novice at making dll's too. I did some research on the net. But I still dont have a clue about what to do when the dll contains things like classes. So please tell me some place where I can read about dll's.
Alternatively,
I am posting my code where I have defined the data types. Someone please tell me what differences will I have to make in the code to make it build-able as a dll...

Code:

#ifndef _GRAPH_H
#define _GRAPH_H

#define INFINITE -1

class Point
{
public:
	float _x, _y, _cost1, _cost2;
	Point(float x, float y, float cost1 = 0, float cost2 = 0);
};

class Graph
{
	Point **points;
	float **adj;
	int capacity;
	int *free;
	int freeIndex;
	int _size;
public:
	int size();
	int insertPoint(Point *point);   //returns a pointHandle
	bool deletePoint(int pointHandle);   //returns 0 if the pointHandle does not exist
	bool editAdj(int pointHandle1, int pointHandle2, float weight);   //returns INFINITE if either of pointHandle1 and pointHandle2 doesnt exist or if weight is negative
	Point point(int pointHandle);   //Blee
	float showAdj(int pointHandle1, int pointHandle2);
	bool editCost(int pointHandle, float cost1, float cost2);
	Graph(int maxSize);
};

Point :: Point(float x, float y, float cost1, float cost2)
{
	_x = x;
	_y = y;
	_cost1 = cost1;
	_cost2 = cost2;
}

Graph :: Graph(int maxSize)
{
	points = new Point *[maxSize];
	free = new int[maxSize];
	freeIndex = maxSize - 1;
	adj = new float *[maxSize];
	for (int i = 0; i < maxSize; i++)
	{
		adj[i] = new float[maxSize];
		points[i] = NULL;
		free[i] = maxSize - 1 - i;
	}
	_size = 0;
	for (i = 0; i < maxSize; i++)
	{
		for (int j = 0; j < maxSize; j++)
		{
			adj[i][j] = INFINITE;
		}
	}
	capacity = maxSize;
}

int Graph :: insertPoint(Point *point)
{
	if (freeIndex < 0) return INFINITE;
	int i = free[freeIndex];
	freeIndex--;
	points[i] = point;
	_size++;
	return i;
}

bool Graph :: deletePoint(int pointHandle)
{
	if (points[pointHandle] == NULL) return 0;
	points[pointHandle] = NULL;
	freeIndex++;
	free[freeIndex] = pointHandle;
	_size--;
	return 1;
}

bool Graph :: editAdj(int pointHandle1, int pointHandle2, float weight)
{
	if (points[pointHandle1] == NULL || points[pointHandle2] == NULL || weight < 0) return 0;
	adj[pointHandle1][pointHandle2] = weight;
	return 1;
}

Point Graph :: point(int pointHandle)
{
	Point p(0,0);
	p = *points[pointHandle];
	return p;
}

float Graph :: showAdj(int pointHandle1, int pointHandle2)
{
	return adj[pointHandle1][pointHandle2];
}

bool Graph :: editCost(int pointHandle, float cost1, float cost2)
{
	if (points[pointHandle] == NULL) return 0;
	points[pointHandle] -> _cost1 = cost1;
	points[pointHandle] -> _cost2 = cost2;
	return 1;
}

int Graph :: size()
{
	return _size;
}

#endif