【941code】求出e的值

题目见http://941code.com/problem/detail/6e266630-3ce2-4eae-b701-9e6afd1289a9/YBT1092

#include<stdio.h>
int main(){
	int n,i=1;
	double e=0,fctr=1;
	scanf("%d",&n);
	for(int i=1;i<=n;i++){
		e+=1/fctr;
		fctr*=i;
	}
	e+=1/fctr;
	printf("%.10lf",e);
	return 0;
}