What is the meaning of '*' and '&' in Golang?


I am new in Golang and I am doing the http://tour.golang.org/. Could anyone explain me lines 1,3,5 and 7 this function especially what '*' and '&' do? I mean by mentioning them in a function declaration, what they are supposed/expected to do? A toy example:

1: func intial1(var1 int, var2 int, func1.newfunc[]) *callproperfunction {
2:
3: addition:= make ([] add1, var1)
4: for i:=1;i<var2;i++ {
5:   var2 [i] = *addtother (randomstring(lengthofcurrent))
6:   }
7: return &callproperfunction {var1 int, var2 int, func1.newfunc[], jackpot}
8: }

It seems that they are pointers like what we have in C++. But I cannot connect those concepts to what we have here. In other words, what '*' an '&' do when I use them in function declaration in Go.

Edit: I know what reference and dereference mean. What I cannot understand is: how we can use pointer to a function is Golang. for example line 1 and 7, what these two line do? we declared a function named intial1 that return a pointer? and in line 7, we call it with arguments using return function.


Answers:


This is possibly one of the most confusing things in Go. There are basically 3 cases you need to understand:

The & Operator

& goes in front of a variable when you want to get that variable's memory address.

The * Operator

* goes in front of a variable that holds a memory address and resolves it (it is therefore the counterpart to the & operator). It goes and gets the thing that the pointer was pointing at, e.g. *myString.

myString := "Hi"
fmt.Println(*&myString)  // prints "Hi"

or more usefully, something like

myStructPointer = &myStruct
// ...
(*myStructPointer).someAttribute = "New Value"

* in front of a Type

When * is put in front of a type, e.g. *string, it becomes part of the type declaration, so you can say "this variable holds a pointer to a string". For example:

var str_pointer *string

So the confusing thing is that the * really gets used for 2 separate (albeit related) things. The star can be an operator or part of a type.