北大ACM poj1517

//1517#include<stdio.h>int i; double e=2.5;int f[10]={1,1,2,6,24,120,720,5040,40320,362880};main(){puts("n e\n- -----------");puts("0 1\n1 2\n2 2.5"); for(i=3;i<=9;i++){ e+=1.0/f[i]; printf("%d %.9f\n",i,e); }}