Towers of Hanoi with True GUI using Win32 and C++

• Download demo - 91.76 KB
• Download source - 23.59 KB 

Introduction

Towers of Hanoi is a puzzle game where there are three stands, each holds number of plates.
The idea here is that you have to move plates in the first stand to the third one, while moving plates you must consider:

1. Size order, meaning when moving a plate you can't put it on a smaller one.
2. Only one plate can be moved at each step.

Please note that I used the recursive method.

Background

Formally, Towers of Hanoi recursive function was given by :

void Hanoi(int platesCount, int from, int dest, int by)
{
	if (platesCount==1)
	{
		printf(
			"Move the plate from %d to %d through %d"
			, from, dest, by);
	}
else
	{
		Hanoi(platesCount -1, from, by, dest);
		Hanoi(1, from, dest, by);
		Hanoi(platesCount -1, by, dest, from);
	}
} 

And here is a conceptual image :

Using the Program

When you launch the application, you will see the next screen: 

Then you have to select whether to let the program step into the solution automatically or not.

Using the Code

While implementing the program, I faced a problem in separating steps since I used the recursive version, so I decided to keep the recursive way. But the call to Hanoi method will happen just first time when "next" or "solve" button is pressed. Inside the Hanoi method, I stored the states of the solution, meaning each time a call happens, the solution of the current step is stored in a list of integers. Since each step in the Hanoi method requires 4 parameters as mentioned above, 4 integers represent parameter is added to the list. Then each time SolveNextStep method is called, the program reads from the list 4 items that represent the state.

Available classes are as follows:

1. HanoiDrawer
2. PlateGUIInfo
3. Tools

Anyway I'll describe methods in HanoiDrawer class that are responsible directly for solving the puzzle.

HanoiDrawer Class

// Advance one step to solve Hanoi
void HanoiDrawer::SolveNextStep()
{
	int platesCount
		, source
		, destination
		, intermediate;

	if(listSavedState.size()==0)
	{
		this->Hanoi(this->iPlatesCount, HanoiDrawer::SOURCE
			, HanoiDrawer::DESTINATION, HanoiDrawer::INTERMEDIATE);
	}

	if(listSavedState.size() % 4 != 0 )
	{
		return;
	}

	platesCount = listSavedState.front();
	listSavedState.pop_front();

	source = listSavedState.front();
	listSavedState.pop_front();

	destination = listSavedState.front();
	listSavedState.pop_front();

	intermediate = listSavedState.front();
	listSavedState.pop_front();

	MovePlateFromTo(source, destination);

	this->iMovesCount++;

	if(iMovesCount == this->GetTotalMovesCount())
	{
		this->solved = true;
	}

	SetDlgItemInt(this->hWnd, this->countContainerResourceId, 
						GetMovesCount(), FALSE);

	SetDlgItemText(this->hWnd, this->fromContainerResourceId
				, PlaceIntToString(source).c_str() );
	SetDlgItemText(this->hWnd, this->toContainerResourceId
				, PlaceIntToString(destination).c_str() );
	SetDlgItemText(this->hWnd, this->throughContainerResourceId
				, PlaceIntToString(intermediate).c_str() );
}

// Draws stands and plates
// then do Invalidate
// this operation is required
// in each step
void HanoiDrawer::ReDraw()
{
	DrawStands();

	DrawPlates();

	Invalidate();
}

// The internal function that is responsible
// about solve the problem.
// platesCount : how many plates
// source : the index of the source
// destination : the index of the destination
// intermediate : the index of the intermediate
void HanoiDrawer::Hanoi(int platesCount, int source, int destination, int intermediate)
{
	if (platesCount == 1)
	{
		listSavedState.push_back(platesCount);
		listSavedState.push_back(source);
		listSavedState.push_back(destination);
		listSavedState.push_back(intermediate);
		return;
	}
	else
	{
		Hanoi(platesCount - 1, source, intermediate, destination);
		Hanoi(1, source, destination, intermediate);
		Hanoi(platesCount - 1, intermediate, destination, source);
		return;
	}
}

Improvements

• The user has the ability to drag and drop the plates, then the program should verify user choice.

Notices

• I tried to focus into the main idea of how I implemented the puzzle to ease understanding of my code. I didn't mention anything about window related tasks.
• Conceptual image is created by MG from Wikipedia:
• http://commons.wikimedia.org/wiki/User:MG
• http://en.wikipedia.org/wiki/Image:Tower_of_Hanoi_4.gif

History

• v1.0 14/7/2007: Main core and functionality