Go- 递归函数

package main
import (	"fmt")
func main() {	/*	   递归函数：在函数内部调用函数本身	   递归调用可能会出现栈溢出，使用懒惰求值的方式解决，go中使用管道和协程解决	*/	res := 0	for i := 0; i < 5; i++ {		res = fibonacci(i)		fmt.Printf("fibonacci(%d) is %d\n", i, res)	}	/*	   输出：	   fibonacci(0) is 1	   fibonacci(1) is 1	   fibonacci(2) is 2	   fibonacci(3) is 3	   fibonacci(4) is 5	*/
	/*	   计算阶乘	*/	res = factorial(30)	fmt.Printf("factorial(30) is %d\n", res) // 输出：factorial(30) is -8764578968847253504---结果溢出
	res = factorial(12)	fmt.Printf("factorial(12) is %d\n", res) // 输出：factorial(12) is 479001600
	/*	   函数之间相互调用形成闭环	*/	fmt.Printf("%2d is odd is %t\n", 16, odd(16))   // 输出：16 is odd is true	fmt.Printf("%2d is odd is %t\n", 15, odd(15))   // 输出：15 is odd is false	fmt.Printf("%2d is odd is %t\n", 0, odd(0))     // 输出： 0 is odd is true	fmt.Printf("%2d is even is %t\n", 16, even(16)) // 输出：16 is even is false	fmt.Printf("%2d is even is %t\n", 15, even(15)) // 输出：15 is even is true	fmt.Printf("%2d is even is %t\n", 0, even(0))   // 输出： 0 is even is false
}
func fibonacci(n int) (res int) {	if n <= 1 {		return 1	}
	res = fibonacci(n-1) + fibonacci(n-2)	return}
func RevSig(nr int) int {	if nr < 0 {		return -nr	}
	return nr}
func odd(nr int) bool {	if nr == 0 {		return true	}
	return even(RevSig(nr) - 1)}
func even(nr int) bool {	if nr == 0 {		return false	}	return odd(RevSig(nr) - 1)}
func factorial(n int) int {	if n <= 1 {		return 1	}
	return n * factorial(n-1)}