(这个是题目)
#include<stdio.h>
int main()
{
double i=1,eps=0,sum=0;
int n=1;
scanf("%lf",&eps);
if(eps>=1){
printf("sum = 1.000000\n");
}
else{
while(1/i>eps) {
sum+=1.0/i*n;
n=-n;
i=i+3;
}
printf("sum = %.6f\n",sum);
}
return 0;
}