abc abc abc GrandTotal <HREF>
All of these examples are strings.
The space character in abc abc
is a legitimate chracter and is part of the string.
Where it is needed for clarity, an square character will be used to
represent a space.
For example, the above string might be shown as: abc□abc
.
In these chapters, string
means a sequence of characters.
Of course, the order of the characters is important.
The string ABCD
is not the same string as DBAC
.
Automata are not limited to processing text. A the string an automaton processes could be a sequence of mouse clicks, a sequence of states of a processor chip, a sequence of voltage levels on a wire, or a sequence of pixels in a digital image. An automaton might model interaction of a user with GUI. The correct sequence of button clicks and other control actions could be guided by the automaton. Or, an automaton could model the interaction of a user with an on-line vendor. Automata are used in many problem domains.
So, although most of these pages show an automaton processing strings of characters, that is just a convenient example.
A particular computer game has a hero progressing through a mysterious cave, chamber by chamber. In each chamber there is a different set of challenges.
What abstract machine could be used to model this game?