Without pointers, when a variable is passed into a function, only a copy of it is used inside the function. We can use pointers to modify values in our structs within a function. But how do we get a pointer to our struct?

Let’s explore this concept using the following struct as an example:

type Employee struct {
  firstName string
  lastName string
  age int
  title string
}

We must first create an instance of Employee and then we create a pointer that will point to this instance. This is done like so:

func main() {
  steve := Employee{“Steve”, “Stevens”, 34, “Junior Manager”}
  pointerToSteve := &steve
}

We can now use this pointer to change the values of the fields for steve. There are two ways to do this in Go:

(*pointerToSteve).firstName

Or a simpler, recommended method:

pointerToSteve.firstName

We can use these pointers to modify structs in our functions. Consider the following example:

func (rectangle *Rectangle) modify(newLength float32){
  rectangle.length = newLength
}

Notice that just inside the function modify() that rectangle is also a pointer. It is dereferenced without the use of the dereferencing operator just like pointerToSteve!

We now have the ability to change Struct values in our functions! Let’s get some practice in!