#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
int Fib(int n)//非递归实现斐波那契
{
	if (n == 1 || n == 2)
		return 1;

	long long int Fib1 = 1;
	long long int Fib2 = 1;
	long long int Fibn = 0;
	for (int i = 2; i < n; i++)
	{
		Fibn = Fib1 + Fib2;
		Fib1 = Fib2;
		Fib2 = Fibn;
	}
	return Fibn;
}

void print(int n)//递归打印一个整数的每一位
{
	if (n > 9)
	{
		print(n / 10);
	}
	printf("%d ", n % 10);
}

int Fac(int n)//递归求n的阶乘
{
	if (n <= 1)
		return 1;
	else
		return n * Fac(n - 1);
}

int my_strlen(char* p)//非递归模拟strlen
{
	int count = 0;
	while (*p != '\0')
	{
		count++;
		p++;
	}
	return count;
}

int my_strlen(char* p)//递归实现strlen
{
	if (*p == '\0')
	{
		return 0;
	}
	else
		return 1 + my_strlen(p + 1);
}

void reverse_string(char* string)//递归模拟实现reverse
{
	char* l = string;
	char* r = string + strlen(string) - 1;
	while (l < r)
	{
		char tmp = *l;
		*l = *r;
		*r = tmp;
		l++;
		r--;
	}
}

int DigitSum(int n)//计算一个数的每位之和（递归实现）
{
	if (n > 9)
		return DigitSum(n / 10) + n % 10;
	else
		return n;
}

int Pow(int n, int k)//递归实现n的k次方
{
	if (k == 0)
		return 1;
	else
		return n * Pow(n, k - 1);
}