View Code of Problem 48

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

int main() {
	int n,i;
	scanf("%d",&n);
	double a[1000]={1.0,2.0};
	for(i=2;i<n*2;i++){
		if(i%2==0){
			a[i]=a[i-1];
		}
		else
			a[i]=a[i-2]+a[i-3];
	}
	
	double sum=0.0;
	for(i=0;i<n*2;i=i+2){
		sum=sum+a[i+1]/a[i];
	}
	printf("%.6lf",sum);
}