BLACK FRIDAY: Save 50% on all my Swift books and bundles! >>

SOLVED: Question : Please see my two simple sets of Structure. Which one is better ?

Forums > 100 Days of SwiftUI
@boat  

Hello,

I've been practicing. Please see my two sets of codes. Both are structures for creating Player, and both could work.

It seems Code 2 is neater ? ( is it common to use closure in a property ?)

Code 1 


struct Player {
    let name: String
    let number: Int

    init (name:String){
        self.name = name
        number = Int.random(in: 1...99)
    }
}

let playerA = Player(name: "Paul")
print(playerA.number)

Code 2


struct Player {
    let name: String
    var number: Int { Int.random(in: 1...99)}
}

let playerA = Player(name:"Paul")
print(playerA.number)

Thank you in advance,

Boat

2      

@roosterboy  HWS+

The two structs are not quite the same.

In the second struct, number is a computed variable that will be recalculated every time it is accessed.

Adjust your test code to this and then try it with each of your Player structs and you will see what I mean:

let playerA = Player(name:"Paul")
print(playerA.number)
print(playerA.number)
print(playerA.number)
print(playerA.number)
print(playerA.number)
print(playerA.number)

3      

@boat  

Oh

@roosterboy, i just tested the code above, I got your point:

in code 2, it is computed property, so the created instance playerA won't have a fixed number, right?

but in code 1, once the instance is created, playerA will have a fixed number, right ?

Boat

2      

@roosterboy  HWS+

in code 2, it is computed property, so the created instance playerA won't have a fixed number, right?

but in code 1, once the instance is created, playerA will have a fixed number, right ?

Yup.

3      

@roosterboy  HWS+

Forgot to mention...

This achieves what you were probably trying to do with the second Player struct:

struct Player {
    let name: String
    let number = Int.random(in: 1...99)
}

You don't need an init since the default memberwise init provided by Swift will give you all you need.

3      

@boat  

Hm...

@roosterboy, in your code let number = Int.random(in: 1...99),

Even if I change let to var, the value assigned to number from Int.random will still remain the same for the instance, right ? It won't generate a new random value everytime the instance is called.

Right ?

2      

@roosterboy  HWS+

Correct, because it is assigned when the struct is created. If you use a var instead of a let, you'll be able to change the value later but until/unless you do so, the property will maintain its initial value.

3      

@boat  

Very clear now.

Thank you @roosterboy

2      

Save 50% in my WWDC sale.

SAVE 50% All our books and bundles are half price for Black Friday, so you can take your Swift knowledge further without spending big! Get the Swift Power Pack to build your iOS career faster, get the Swift Platform Pack to builds apps for macOS, watchOS, and beyond, or get the Swift Plus Pack to learn advanced design patterns, testing skills, and more.

Save 50% on all our books and bundles!

Archived topic

This topic has been closed due to inactivity, so you can't reply. Please create a new topic if you need to.

All interactions here are governed by our code of conduct.

Swift breaks down barriers between ideas and apps, and I want to break down barriers to learning it. I’m proud to make hundreds of tutorials that are free to access, and I’ll keep doing that whatever happens. But if that’s a mission that resonates with you, please support it by becoming a HWS+ member. It’ll bring you lots of benefits personally, but it also means you’ll directly help people all over the world to learn Swift by freeing me up to share more of my knowledge, passion, and experience for free! Become Hacking with Swift+ member.
Click here to visit the Hacking with Swift store >>
 
Unknown user

You are not logged in

Log in or create account
 

Link copied to your pasteboard.