斐波那契数列的递归和非递归实现

非递归

#include <iostream>
using namespace std;

int fib(int n)
{
	if(n < 2) return n < 0 ? 0:n;
	
	int cur_2 = 0 , cur_1 = 1 , cur = 0;
	
	// 将从2到n的斐波那契数都计算出来，层层累加 
	for(int i = 2; i <= n; i++)
	{
		cur = cur_2 + cur_1;
		cur_2 = cur_1;
		cur_1 = cur;
	}
	return cur;

}
int main(int argc, char* argv[])
{
	for(int i = -1; i < 6; i++)
	{
		cout << fib(i) << " ";
	}
	cout << endl;
	return 0;
	
}

　　递归

int recursiveFib(int n )
{
	if(n < 2) return n < 0 ? 0 : n;
	
	else return recursiveFib(n - 1) + recursiveFib(n - 2); 
}