Go Exercise: Fibonacci closure

fibonacci.go

package main

import "fmt"

// fibonacci is a function that returns
// a function that returns an int.
func fibonacci() func() int {
	num, add := 1, -1
	return func() int {
		num, add = num+add, num
		return num
	}
}

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