Assign a new value to Golang structure field

Question

I have a problem with structure fields.

I\'ve created a class Point with one method Move() that increases or decreases object variable

Answer 1

You need to use a pointer here or you are only changing a copy of the original object every time. Everything is passed by value in go.

type Point struct {
  x, dx int
}

func (s *Point) Move() {
  s.x += s.dx
  log.Printf("New X=%d", s.x)
}

func (s *Point) Print() {
  log.Printf("Final X=%d", s.x)
}

func main() {
  st := Point{ 3, 2 };
  st.Move()
  st.Print()
}

Answer 2

That's the difference between pointer receiver and value receiver

http://golang.org/doc/faq#methods_on_values_or_pointers