What is difference between create object with init and () in Swift [duplicate]

Question

class A {

    private var value: Int

    init(value: Int) {
        self.value = value
    }
}

We have class A and what is the difference between I create this object by using A.init(value: 5) and A(value: 5)? Thanks

Answer 1

There is no functional difference between the two. Both styles will call the same initializer and produce the same value.

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Most style guides that I've seen prefer to leave out the explicit .init-part in favor of the shorter A(value:) syntax — that also resembles the constructor syntax in many other languages.

That said, there are some scenarios where it's useful to be able to explicitly reference the initializer. For example:

• when the type can be inferred and the act of initialization is more important than the type being initialized. Being able to call return .init(/* ... */) rather than return SomeComplicatedType(/* ... */) or let array: [SomeComplicatedType] = [.init(/* ... */), .init(/* ... */)]

• when passing the initializer to a higher order function, being able to pass "something".map(String.init) rather than "something".map({ String($0) })

Again, it's a matter of style.