package main

import "fmt"

// fibonacci is a function that returns
// a function that returns an int.
func fibonacci() func() int {
	prevFibNumb := 1
	currFibNumb := 0

	return func () int {

		defer func (){prevFibNumb = currFibNumb - prevFibNumb}()
		defer func (){currFibNumb += prevFibNumb}()

		return currFibNumb
	}
}

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