Datasheet

10
Part I: Getting to the Starting Line
No, what will make you a good programmer is taking the time to really under-
stand the world of the user, and what you can do with a computer to make
things better. For example, when I travel I often zone out on the fact that even
though it looks like monopoly money, foreign currency actually does amount
to something in dollars. I could use a computer to keep track of my budget
and convert foreign currency into dollars for me. Writing a program simply
involves detailing the steps the computer needs to follow (in a language the
computer understands — but I’ll get to that). You know, something like
subtract the amount he just spent from the amount he started with
or
multiply the amount in foreign currency times the exchange rate.
Is it hard? No, not really. It can be pedestrian, but even more often it is fun.
Why a Computer Program Is Like a
Peanut Butter and Jelly Sandwich
At its heart (yes, it does have one), computer programming is actually not
that alien to most people. If you don’t believe me, take the following program-
ming test. Now, don’t peek ahead for the answer. Okay?
The Never Fail Programming Test:
Write down the recipe for making a peanut butter and jelly sandwich.
Answer:
If what you wrote down looks anything like
Recipe: Peanut Butter and Jelly Sandwich
Ingredients
Peanut Butter
Jelly
2 slices of bread
Directions
Place the two slices of bread close to each other
Spread peanut butter on one slice of bread
Spread jelly on the other slice of bread
Put one slice of bread on top of the other
then you’re ready to go.
While this example may seem overly simple, it generally illustrates what
programming is all about. When you write a program in Objective-C, all you
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