DAY 4

Complex data types, part 2

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Today we’re going to finish our look at data types by examining type annotation, which is Swift’s way of letting us dictate exactly what data type each variable and constant should be. Once that’s done we’ll summarize what’s covered, then try another checkpoint so you can evaluate what you’ve learned so far.

I know, you’re probably sick of data types at this point, but as Eric Raymond said, “good data structures and bad code works a lot better than the other way around.”

Today you’ll learn about type annotation, then go through the summary and checkpoint. There’s some optional extra reading that I recommend you read, along with a short test to help make sure you’ve understood what was taught.

Today ought to take you a lot less than an hour to complete, but that’s okay – day 13 will probably take more than an hour, so it all balances out!

1. How to use type annotations
   • Optional: Why does Swift have type annotations?
   • Optional: Why would you want to create an empty collection?
   • Test: Type annotations
2. Summary: Complex data
3. Checkpoint 2

Tip: Even though the checkpoint doesn’t ask much, don’t be surprised if you spend some time kind of staring at the screen wondering what to do. That isn’t a bad sign – in fact, I’d say it’s a good sign. I firmly believe there is no learning without struggle, so don’t be afraid to fight for it!

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