View Code of Problem 71

#include<stdio.h>
int main(){
	int n,i;
	double sum=0.0;
	scanf("%d",&n);
	double a=2.0;
	double b=1.0;
	double t;
 
	for(i=0;i<n;i++){
		sum +=a/b;
		t=a;
		a=a+b;
		b=t;
		//printf("%d %d %d %d\n",t,a,b,sum);
	}
	printf("%.2lf",sum);
        return 0;
}