Which version of XCode are you using? When I pasted your code into a XCode 11.5 playground I had a bunch of errors but none of them matched the ones you reported.
Keep in mind that this book is 5 years old, and Swift has changed significantly in that time. The book’s code won’t work in the current version of XCode without some tinkering. This thread has code for Chapter 3 that appears to be fairly up to date for the current version of Swift.