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Wizard sprite
OK sprite
New sprite
Figure 9-32: The user interface for the Math Wizard application
The application contains three sprites: the Wizard sprite, which gives
the instructions to the player, and the OK and New sprites, for the OK and
New Game buttons, respectively. It also uses the two lists illustrated in
Figure 9-33.
Answer of first puzzle
Instructions for first puzzle
End of first puzzle
Answer of second puzzle
...
Figure 9-33: The two lists used by the Wizard sprite
The instr list (right) contains 11 puzzle records. Each record includes
(a) the answer of the puzzle, (b) the instructions, and (c) an empty ele-
ment to mark the end of that record. The entries in the list on the left
(named index) identify the starting index of each puzzle in the instr list.
For example, the second element in the index list is 9, which means the
record of the second puzzle starts at the ninth position in the instr list, as
illustrated in Figure 9-33. Let’s outline a strategy for developing this game:
1. When the user starts a new game, select a random number between 1
and 11 (because our game currently contains 11 puzzles).
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