Struct defined in a function

Question

I defined a struct in a function, no matter how many times I invoked the function, struct definition seems like always be the first time function invoked.

the 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()

the result is :

  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 am not familiar with swift, can any body explain why?

Sergey Kalinichenko · Accepted Answer · 2014-09-06 12:01:14Z

6

This code snippet illustrates the way the static attributes are initialized in Swift. It shows that static attributes are initialized only once, at the first invocation. Subsequent invocations do not "reassign" the value: you can see that incrementing g has no effect on the value of attr, which remains unchanged.

answered Sep 6, 2014 at 12:01

Sergey Kalinichenko

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1 Comment

6174 Over a year ago

Thx, I think I get the answer.

user4007645 · Accepted Answer · 2014-09-07 05:55:34Z

0

simply use instance of the struct and you 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

answered Sep 7, 2014 at 5:55

user4007645

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