A Tour of Go. Exercise: Fibonacci closure. Let's have some fun with functions. Implement a fibonacci function that returns a function (a closure) that returns successive fibonacci numbers.

exercise-44.go

package main

import "fmt"

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

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