计算 1 - 1 / 2 + 1 / 3 - 1 / 4 + 1 / 5 …… + 1 / 99 - 1 / 100 的值

//计算 1 - 1 / 2 + 1 / 3 - 1 / 4 + 1 / 5 …… + 1 / 99 - 1 / 100 的值
#include<stdio.h>
#include<stdlib.h>
int main()
{
  int  den = 1;  //分母
  double member = 1.0;      //分子
  double sum = 0.0;
  int flag = 1;
  for (int i = 0; i < 100; i++)
  {
    sum +=flag* member / den;
    den++;
    flag *= -1;

  }
  printf("%lf\n", sum);
  system("pause");
  return 0;
}