go 递归函数

一、什么是递归函数？

　　当一个函数在其函数体内调用自身，则称之为递归。

二、引用经典例子：斐波那切数列

package main

import "fmt"

func main(){
	result := 0
	for i := 0; i <= 10; i++ {
		result = fibonacci(i)
		fmt.Printf("fibonacci(%d) is: %d
", i, result)
	}
}

func fibonacci(n int )(res int){
	if n <= 1{
		res = 1
	}else {
		res = fibonacci(n-1) + fibonacci(n-2)
	}
	return
}
//输出：

fibonacci(0) is: 1
fibonacci(1) is: 1
fibonacci(2) is: 2
fibonacci(3) is: 3
fibonacci(4) is: 5
fibonacci(5) is: 8
fibonacci(6) is: 13
fibonacci(7) is: 21
fibonacci(8) is: 34
fibonacci(9) is: 55
fibonacci(10) is: 89

　　调用前两个数，相加，得到值。

三、相互闭环调用

package main

import "fmt"

func main() {
	fmt.Printf("%d is event: is %t 
", 16, even(16))
	fmt.Printf("%d is odd: is %t
", 17, odd(17))
	fmt.Printf("%d is odd: is %t
", 18, odd(18))
}

func even(nr int) bool {
	if nr == 0 {
		return true
	}
	return odd(RevSign(nr) - 1)
}

func odd(nr int) bool {
	if nr == 0 {
		return false
	}
	return even(RevSign(nr) - 1)
}

func RevSign(nr int) int {
	if nr < 0 {
		return -nr
	}
	return nr
}
输出：

16 is event: is true
17 is odd: is true
18 is odd: is false