This chapter covers
- What a function is
- How a function is created and used
- How to pass data to a function
- How to receive data from a function
You’ve reached the eighth milestone: reuse your code. Before you get started, here’s the main thing you need to know about functions: functions exist so that you can reuse and clean your code.
Read on, and I’ll explain why you might want to have reusable code.
You’re about to find out what a function is. I’ll start with a simple example.
Imagine that you’re playing a game on your computer. In this game, your character needs to jump over obstacles. You have three ways to make your character jump:
- Press the J key.
- Press the up-arrow key.
- Press the spacebar.
Although it sounds like a simple thing, making a character jump in a game could take 40 lines of code or more.
Now think about the jump taking 40 lines of code. I won’t put a big block of code here, but look at the diagram in figure 8.1.
All three blocks of code do the same thing: make the character jump. As shown in the figure, you could type the same 40 lines of code for jumping for all three events, but there are a few problems with that: