package main

import "fmt"

// fibonacci is a function that returns
// a function that returns an int.
func fibonacci() func() int {
   n := 0
   a := 0
   b := 1
   c := a + b

   return func() int {
		var ret int
		switch {
		  case n == 0:
		   	   n++
			   ret = 0
		  case n == 1:
			   n++
			   ret = 1
		  default:
			   ret = c
			   a = b
			   b = c
			   c = a + b
		}
		return ret
	}
}

func main() {
	f := fibonacci()
	for i := 0; i < 10; i++ {
		fmt.Println(f())
	}
}