斐波那契数列C++

#include <iostream>
using namespace std;
int main()
{
	int f1=1;
	int f2=1;
	int fn;
	cout<<f1<<" ";
	cout<<f2<<" "; 
	for(int i=0;i<20;i++)
	{
		int fn=f1+f2;
		cout<<fn<<" ";
		f1=f2;
		f2=fn;
		
	}
	return 0;
}