View Code of Problem 48

#include<iostream>
#include<cmath>
#include<cstdio>
using namespace std;

int main() {
	int n;
	cin >> n;
	int a, b, c;
	a = 1;
	b = 2;
	c = 3;
	double y, sum=0;
	
	for (int i = 0; i < n; i++) {
		y = (double)b / a;
		c = b;
		b = a + b;
		a = c;
		sum = sum + y;
	}
	printf("%.6lf", sum);
	return 0;
}