View Code of Problem 48

#include<stdio.h>
main(){
	int i,n;
	double a,b,c,sum;
	sum=0;
	a=1;
	b=2;
	scanf("%d",&n);
	for(i=1;i<=n;i++){
		sum=sum+b/a;
		c=b;
		b=a+b;
		a=c;
	}
	printf("%.6lf\n",sum);
}