Difference between struct static func vs class static func in swift?

Question

I am not able to find any difference between class static function to struct static function. As I know class static function can not be inherited and struct does not have an option for inheritance.

Please do not get confused by static func and class func in class.

class a {
    static func myMethod1() {
    }
}

vs

struct a {
    static func myMethod1() {
    }
}

Answer 1

This is kind of a stretch, but due to the reference vs value semantics of class and struct types, respectively, there is subtle difference in in the realization of a case where you want to make use of a type method (static) to mutate a private property of the type, given an instance of the type has been supplied. Again, kind of a stretch, as this focuses on differences in implementation details, and not on a concrete difference between the two.

In the class case, an immutable reference can be supplied to the static method, which in turn can be used to mutate a private instance member of the type. In the case of the struct, the instance of the type naturally needs to be supplied as an inout parameter, as changing the value of an instance member of a value type also means changing the value of the instance itself.

class A {
    private(set) var i: Int = 0
    static func foo(_ bar: A) { 
        bar.i = 42
    }
}

struct B {
    private(set) var i: Int = 0
    static func foo(_ bar: inout B) { 
        bar.i = 42  
    }
}

let a = A()
var b = B()

A.foo(a)
print(a.i) // 42
B.foo(&b)
print(b.i) // 42