Datasheet

12
Part I: Let’s Get Started
As detailed as these instructions might seem to be, this is not a program.
This is called an algorithm. An algorithm is a description of the steps to be
performed, usually at a high level of abstraction. An algorithm is detailed but
general. I could use this algorithm to repair any of the flat tires that I have
experienced or ever will experience. But an algorithm does not contain suf-
ficient detail for even our intentionally obtuse human computer to perform
the task.
The Tire Changing Language
Before we can write a program, we need a language that we can all agree on.
For the remainder of this book, that language will be C++, but I use the newly
invented TCL (Tire Changing Language) for this example. I have specifically
adapted TCL to the problem of changing tires.
TCL includes a few nouns common in the tire-changing world:
✓ car
✓ tire
✓ nut
✓ jack
✓ toolbox
✓ spare tire
✓ wrench
TCL also includes the following verbs:
✓ grab
✓ move
✓ release
✓ turn
Finally, the TCL-executing processor will need the ability to count and to
make simple decisions.
This is all that the tire-changing robot understands. Any other command
that’s not part of Tire Changing Language generates a blank stare of incom-
prehension from the human tire-changing processor.
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