View Code of Problem 71

#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
	int n;
	double sum;
	cin>>n;
	double a[n]={0};
	a[1]=1;a[2]=2;
	for(int i=3;i<=n+1;i++)
	  a[i]=a[i-1]+a[i-2];
	for(int j=1;j<=n+1;j++)
	{
		sum=sum+double(a[j+1]/a[j]);
	  } 
	  
	  cout<<fixed<<setprecision(2)<<sum<<endl;
 }