fib.go

package main

import "fmt"

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

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