分数1/1-1/2+1/3-1/4+1/5 …… + 1/99 - 1/100 求和

#include<stdio.h>
int main()
{
  float sum1 = 0;
  float sum2 = 0;
  for (int i = 1; i <= 100; i = i + 2)
  {
    sum1 += 1.0 / i;
  }
  for (int i = 2; i <= 100; i = i + 2)
  {
    sum2 -= 1.0 / i;
  }
  printf("%f\n", sum1 + sum2);
  return 0;
}

#include<stdio.h>
int main()
{
  int flag = 1;
  float sum = 0;
  for (int i = 1; i <= 100; i++)
  {
    sum += flag * 1.0 / i;
    flag = -flag;
  }
  printf("%f", sum);
  return 0;
}