View Code of Problem 71

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