Chapter 1

Note
9.2.3 The Controller
As described above, 'my fleet' appears to be a rather odd name in this
context. This is because it's carried over from the full Battleships game in
which the 'my fleet' object really does represent the player's fleet, which, the
opponent, on another phone, is trying to sink. Also, note that the program
refers to a shot at a particular square as a 'hit request'. A square marked as
'hit' is one that has been fired at: it doesn't mean that a ship at that square
has been successfully struck.
In the MVC paradigm, we saw the following:
� The model contains the application data – in Solo Ships, most of the model is
contained in the game engine, though the view's zoom state is also model data.
� The view draws the model in a way that is meaningful to the human user.
� The controller updates the model, and requests view redraws, in response to various
kinds of event – including user interactions.
The CGameController class implements controller functionality. It owns the model
(CGameEngine, and an iZoomFactor member), and ensures that the model state is saved
to file. Finally, the controller handles all events that cause the model (and therefore the view)
to change. In Solo Ships, there are two types of events:
� User interactions from the fleet view – handled by the controller as the implementer of
the MGameViewCmdHandler interface.
� Commands from the app UI – most app UI CmdXxxL() functions are prechecked by
the app UI, and then implemented by some controller function.
For many applications, a separate controller class like this isn't needed. It's OK to put many
of the controller functions inside the app UI or the model, provided that all the persistent data
is inside the model.
9.3 Engine Classes
We've seen about as much of the high-level view as we can realistically take in. Now it's time
to get down to some more detail. Let's start with the engine, which is declared in engine.h
and implemented in engine.cpp.
There are three classes (as shown in Figure 9.3):
Class Description
CGameEngine The engine itself, which includes two fleets(iMyFleet and
iOppFleet), and some utility functions.
TFleet A fleet. The same class is used to represent'my fleet', and to represent
the 'opponent fleet'.
TShip A ship. A ship object contains a data member indicating whether it's a
Battleship (the largest ship), Cruiser, Destroyer, or Frigate (the
smallest).
In UML, that's