poj1517 u Calculate e

#include<stdio.h>double fac(int n){       float f;   if(n==0||n==1)   f=1;   else if(n>1)   {           f=fac(n-1)*n;   }   return f;}int main(){double sum=0;double a;int i;printf("n e\n");printf("- -----------\n");for(i=0;i<10;i++){ a = 1/fac(i);sum = a +sum;printf("%d %.9f\n",i,sum);           }}