Solution to Exercise: Fibonacci closure from http://tour.golang.org/#43

NextFib.go

package main

import "fmt"

// fibonacci is a function that returns
// a function that returns an int.
func fibonacci() func() int {
    // first 2 negative fib numbers - see bidirectional sequence at http://en.wikipedia.org/wiki/Fibonacci_number
    fib1 := -1 
    fib2 := 1
    return func() int {

        nextFib := fib1 + fib2
        fib1 = fib2
        fib2 = nextFib
        return nextFib
    }

}

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