View Code of Problem 71

#include<stdio.h>
int main()
{
	int n;
	double x,sum=0.0,a=2,b=1;
	scanf("%d",&n);
	for(int i=1;i<=n;i++)
	{
		sum+=a/b;
		x=a;
		a=a+b;
		b=x;
	}
	printf("%.2lf",sum);

    return 0;
}