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PLUS

# Can someone please explain this code

This was the answer to a code challenge. We have gone over stucts, initializers, and optionals though I thought this was a little behond the scope of the lessons so far. I only found the answer by Googling and am still lost.

What's happening here? What's the use of this struct?

struct Book { let title: String let author: String let price: String? let pubDate: String?

```init?(dict: [String: String]) {
guard let title = dict["title"], let author = dict["author"] else {
return nil
}

self.title = title
self.author = author
self.price = dict["price"]
self.pubDate = dict["pubDate"]
}
```

}

## 2 Answers

Structs are a type of framework to build objects in Swift.

Think of a struct, and classes for that matter, as a category. The Book struct defines a book as having an author, title, price, pubDate. This could be used in a book store's database, we can even add a var quantity to the struct so we can track how many are in the store.

For example, we have 2 books (I'll skip initialization):

```let bookOne = Book()
let bookTwo = Book()
```

Now the store has sold 2 copies of bookOne and received 27 of bookTwo in a shipment. We could adjust the quantities based on these numbers:

```bookOne.quantity -= 2   \\ 2 books sold
bookTwo.quantity += 27 \\ 27 copies received
```

They are both books, they have the same property categories (price, quantity, title, etc.), so rather than create the framework everytime you add a book, the Book struct allows you to build the framework once and use it across multiple versions of books. Hope this helps

PLUS

Thanks for the response. I appreciate you explaining the use of structs but what I'm looking for was a specific example of how to use this struct which was the answer to a lesson within the iOS course.

struct Book { let title: String let author: String let price: String? let pubDate: String?

```init?(dict: [String: String]) {
guard let title = dict["title"], let author = dict["author"] else {
return nil
}

self.title = title
self.author = author
self.price = dict["price"]
self.pubDate = dict["pubDate"]
```

} }