View Code of Problem 48

#include <stdio.h>
int main(){
	int n;
	scanf("%d",&n);
	int i,a[n+1];
	a[0]=1;
	a[1]=2;
	for(i=2;i<n+1;i++){
		a[i]=a[i-1]+a[i-2];
	}
	double b,sum=0;
	for(i=1;i<=n;i++){
		b=(double)a[i]/a[i-1];
		sum+=b;
	}
	printf("%.6lf",sum);
}