Exercise 43 (Fibonacci Closure) from tour.golang.org

43_fibonacci_closure.go

package main

import "fmt"

// #43, A Fibonacci closure
// fibonacci is a function that returns
// a function that returns an int.
func fibonacci() func() int {
  x, y := 1, 0
	return func() int {
		z := x + y
		x = y
		y = z
		return x
	}
}

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