View Code of Problem 48

#include<stdio.h>
#include<math.h>
int main()
{
	int a1,b1,a2,b2,n,i,j;
	double sum=0;
	scanf("%d",&n);
	a1=1,a2=2,b1=2,b2=3;
	for(i=0;i<n;i++)
	{
		if(i==0)
		{
			sum+=2/1.0;
		}else if(i==1){
			sum+=3/2.0;
		}else{
			int b3,a3;
			b3=b1+b2;
			a3=a1+a2;
			sum+=(b1+b2)*1.0/(a1+a2);
			b1=b2,b2=b3,a1=a2,a2=a3;
		}
	}
	printf("%.6lf\n",sum);
	return 0;
}