http://go-tour-jp.appspot.com/#44

answer_exercise_gotour_44.go

package main

import "fmt"

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

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