State Pattern in C++ Applications

// GameManager.cpp: implementation of the CGameManager class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "GameState.h"
#include "StatePattern_Game.h"
#include "GameManager.h"
#include "IntroductionState.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CGameManager::CGameManager()
{
	m_pGameState = NULL;

	// by default, we start with the introduction mode...
	ChangeState( CIntroductionState::Instance() );
}

CGameManager::~CGameManager()
{
}

void CGameManager::ChangeState(CGameState * pState)
{
	ASSERT(pState);
	if ( pState != m_pGameState )
	{
		m_pGameState = pState;
		m_pGameState->Init();
	}
}

void CGameManager::ProcessKeyboardEvent(char nKey)
{
	ASSERT(m_pGameState);
	m_pGameState->KeyboardEvent(this, nKey);
}

void CGameManager::Update()
{
	ASSERT(m_pGameState);
	m_pGameState->Update(this);
}

void CGameManager::Draw(CDC * pDC)
{
	ASSERT(m_pGameState);
	m_pGameState->Draw(this, pDC);
}

void CGameManager::SetRect(CRect & rect)
{
	ASSERT(m_pGameState);
	CGameState::m_Rect = rect;
	m_pGameState->Resize();
}