计算1/1-1/2+1/3-1/4+1/5 …… + 1/99

# include <stdio.h>
int main()
{
 int i;
double sum;
 sum=0.0;
 for(i=1 ;i<=100 ;i++ )
 {if(i/2==0)
  sum=sum+1.0/i*(-1);
  else
   sum=sum+1.0/i;}
 printf("%lf",sum);
 getchar();
 return 0;
}