题目：
Let‘s have some fun with functions. Implement a fibonacci function that returns a function (a closure) that returns successive fibonacci numbers (0, 1, 1, 2, 3, 5, ...).
代码：
package main
import "fmt"
// fibonacci is a function that returns
// a function that returns an int.
func fibonacci() func() int {
a, b, c := 0, 1, 0
return func () int {
c, a, b = a, b, a+b
return c
}
}
func main() {
f := fibonacci()
for i := 0; i < 10; i++ {
fmt.Println(f())
}
}
运行结果：
0 1 1 2 3 5 8 13 21 34
原文：http://www.cnblogs.com/chpx/p/5523010.html