View Code of Problem 48

#include<stdio.h>
#include<math.h>
int main()
{
	int n,i;
	double a[11];
	while(~scanf("%d",&n))
	{
		double sum = 0.0;
		a[1]=2*1.0/1;
		a[2]=3*1.0/2;
		a[3]=5*1.0/3;
		a[4]=8*1.0/5;
		a[5]=13*1.0/8;
		a[6]=21*1.0/13;
		a[7]=34*1.0/21;
		a[8]=55*1.0/34;
		a[9]=89*1.0/55;
		a[10]=144*1.0/89;
		for(i=1;i<=n;i++)
		{
			sum += a[i];
		}
		printf("%.6lf\n",sum);
	}
	return 0;
}