Tour of Go 2.0

Exercise: Fibonacci closure

Put closures to work.

Implement fibonacci so that it returns a closure. Each time you call that closure, it returns the next number in the Fibonacci sequence: 0, 1, 1, 2, 3, 5, …

The state (the previous two numbers) lives inside the closure — no global variables needed.

main.go ▶ Run in Playground 
package main

import "fmt"

// fibonacci is a function that returns
// a function that returns an int.
func fibonacci() func() int {
}

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