Pass value of variable as Reference in Swift

Question

I want to pass the value as reference.

var a = "*"
var b = ""

func hello(c: inout String){
    b = c
    a = "**"
    print(b)
    print(c)
}

hello(c: &a)

The output for the above is

B: *

C: **

I want to change the value of B as well as in, I want to pass the reference to B not the value

I want the output to be

B: **

C: **

Any help would be appreciated. Thanks in advance

Mutating `a` inside the function is already undefined behaviour, and your code crashes with `Simultaneous accesses to 0x1003b92b0, but modification requires exclusive access.` — Martin R, May 21 '18 at 11:59
Related: [Is Swift pass-by-value or pass-by-reference](https://stackoverflow.com/questions/27364117/is-swift-pass-by-value-or-pass-by-reference). You should also read the [Classes and Structures](https://developer.apple.com/library/content/documentation/Swift/Conceptual/Swift_Programming_Language/ClassesAndStructures.html) chapter of the Swift book, it will help you understand value- and reference types in Swift. — Dávid Pásztor, May 21 '18 at 12:06
My variable A is in another class and B is in another class, Now if I change value of A from another class then it should be updated here — Parth Soni, May 21 '18 at 12:14

score 0 · Answer 1 · answered May 21 '18 at 12:03

0

Something that you can do is this

var b = ""
var a = "*"{
    didSet{
        b = a
    }
}

and when the value of a changes the b will have the value of a

answered May 21 '18 at 12:03

Vasilis D.

1 Answers1