View Code of Problem 48

#include<iostream>
#include<iomanip>
using namespace std;
int main()
{
  double x=2,y=1,a,b,sum=0;
  int n;
  cin>>n;
  for(int i=0;i<n;i++)
  {
  	 sum=sum+(x/y);
  	 x=x+y;
  	 y=x-y;
  	  	
  }
  cout<<fixed<<setprecision(6)<<sum<<endl;
}