hdu 1012

水题，按照公式直接求

AC：

#include<stdio.h>#include<string.h>int f(int x){return x==0? 1:f(x-1)*x;//递归求阶乘}int main(){int n,i,j;double sum[11];memset(sum,0,sizeof(sum));printf("n e\n- -----------\n0 1\n1 2\n2 2.5\n");sum[2]=2.5;for(int i=3;i<=9;i++){sum[i]=sum[i-1]+1.0/f(i);//double型数据是要乘1.0的，别忘了printf("%d %.9lf\n",i,sum[i]);}return 0;}