C 递归与迭代的使用切换

分别用递归和迭代实现斐波那契数列

my_main.c

#include"my_declare.h"
#include

int main()
{
	printf("%d\n", hd_fibonacci(4));
	printf("%d\n", dd_fibonacci(5));
}

my_func.c

#include"my_declare.h"
/*
**递归函数
*/
long hd_fibonacci(int n)
{
	if (n <= 2) {
		return 1;
	}
	else
	{
		return hd_fibonacci(n - 1) + hd_fibonacci(n - 2);
	}
}
/*
**迭代函数
*/
long dd_fibonacci(int n)
{
	long result;
	long previous_result;
	long next_older_result;

	result = previous_result = 1;

	while (n > 2) {
		n -= 1;
		next_older_result = previous_result;
		previous_result = result;
		result = previous_result + next_older_result;
	}
	return result;
}

my_declare.h

long hd_fibonacci(int n);
long dd_fibonacci(int n);