a43.go

package main
 
import "fmt"
 
// fibonacci is a function that returns
// a function that returns an int.
func fibonacci() func() int {
    a := []int{0, 1, 1}
    i := 0
    return func() int {
        i++
        if i < len(a) {return a[i]}
        a[1], a[2] = a[2], a[2] + a[1]
        return a[2]
    }
}
 
func main() {
    f := fibonacci()
    for i := 0; i < 10; i++ {
        fmt.Println(f())
    }
}