View Code of Problem 71

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