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A string defined in a function

I have defined the structure in a function, no matter how many times I have called that function, the structure definition seems to, as always, will be called the first time.

code:

    var g = 0
    func f() {
        struct InnerStruct{
            static var attr:Int = g
        }
        println("static attr value is \(InnerStruct.attr), g is \(g)")
    }

    f()
    g++
    f()
    g++
    f()

result:

  static attr value is 0, g is 0
  static attr value is 0, g is 1
  static attr value is 0, g is 2
  Program ended with exit code: 0

I'm not familiar with swift, can anyone explain why?

+3


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2 answers


This code snippet illustrates a way to initialize attributes static

in Swift. It shows that attributes are static

initialized only once on the first call. Subsequent calls do not "reassign" the value: you can see that incrementing g

does not affect the value attr

, which remains unchanged.



+6


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just use an instance of the struct and get the desired result

var g = 0

func f() {
    struct InnerStruct{
        var attr:Int = g
    }
    println("static attr value is \(InnerStruct().attr), g is \(g)")
}

f()
g++
f()
g++
f()


result:

static attr value is 0, g is 0
static attr value is 1, g is 1
static attr value is 2, g is 2
0


source






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