What is a state?

Before we get into any kind of implementation, it's necessary to understand what we're dealing with. If you've been reading up on any kind of game development material before, you probably came across the term state. It can mean different things, depending on its context. In this case, a state is any one of the many different layers of your game, like the main menu, the intro that plays before the menu is shown, or the actual game-play. Naturally, each one of these layers has its own way of updating itself and rendering its contents onto the screen. The game developer's job when utilizing this system is to break down a given problem into separate, manageable states and transitions between them. This essentially means that if you are presented with the problem of having a menu in the game, the solution would be creating two states, one for the menu and one for your game-play, and transitioning between the two at appropriate times.