A simple way for switching states

One of the simplest ways to handle states is to load everything we want at the game's initialization stage, but only draw and update the objects specific to each state. Let's look at an example of how this could work. First, we can define a set of states we are going to use:

enum game_states
{
  MENU = 0,
  PLAY = 1,
  GAMEOVER = 2
};

We can then use the Game::init function to create the objects:

// create menu objects
m_pMenuObj1 = new MenuObject();
m_pMenuObj1 = new MenuObject();

// create play objects
m_pPlayer = new Player();
m_pEnemy = new Enemy();

// create game over objects…

Then, set our initial state:

m_currentGameState = MENU;

Next, we can change our update function to only use the things we want when in a specific state:

void Game::update()
{
  switch(m_currentGameState)
  {
    case MENU:
      m_menuObj1->update();
      m_menuObj2->update();
      break;

    case PLAY:
      m_pPlayer->update();
      m_pEnemy->update();

    case GAMEOVER...