View Code of Problem 71

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