A Tour of Go | Exercise: Fibonacci closure

fibonacci_closure.go

package main

import "fmt"

// fibonacci is a function that returns
// a function that returns an int.
func fibonacci() func() int {
    fib := 0
    return func() int {
        first, second := 0, 1
        for i := 0; i < fib; i++ {
            first, second = second, first + second
        }
        fib++
        return first
    }
}

func main() {
    f := fibonacci()
    for i := 0; i < 10; i++ {
        fmt.Println(f())
    }
    f2 := fibonacci()
    for i := 0; i < 20; i++ {
        fmt.Println(f2())
    }
}