C语言习题12

题目名称：分数求和

题目内容：计算1/1-1/2+1/3-……+1/99-1/100的值，打印出结果

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