Differences between “static var” and “var” in Swift

Question

What is the main difference between \"static var\" and \"var\" in Swift? Can someone explain this difference to me, possibly with a little example?

Answer 1

A static var is property variable on a struct versus an instance of the struct. Note that static var can exist for an enum too.

Example:

struct MyStruct {
    static var foo:Int = 0
    var bar:Int
}

println("MyStruct.foo = \(MyStruct.foo)") // Prints out 0

MyStruct.foo = 10

println("MyStruct.foo = \(MyStruct.foo)") // Prints out 10

var myStructInstance = MyStruct(bar:12)

// bar is not 
// println("MyStruct.bar = \(MyStruct.bar)")

println("myStructInstance = \(myStructInstance.bar)") // Prints out 12

Notice the difference? bar is defined on an instance of the struct. Whereas foo is defined on the struct itself.