View Code of Problem 71

#include <bits/stdc++.h>
using namespace std;
int main()
{
	double a[999];
	double b[999];
	double f[999];
	f[0]=1.0;
	f[1]=2.0;
	for(int i=2;i<999;i++)
	{
		f[i]=f[i-1]+f[i-2];
	}
	int n;
	cin>>n;	
	b[0]=0;
	for(int i=1;i<=n;i++)
	{
		a[i]=f[i]/f[i-1];
		b[i]=b[i-1]+a[i];
	}
	
	printf("%.2lf",b[n]);
	return 0;
 }