public static int binSearch (double[] list, double item)
{
   int bottom = 0;                 // lower bound of subarray
   int top = list.length - 1;         // upper bound of subarray
   int middle;                        // middle of subarray
   boolean found = false;            // to stop if item found
   int location = -1;              // index of item in array

   while (bottom <= top && !found)
   {
      middle = (bottom + top)/2;
      if (list[middle] == item)    // success
      {
         found = true;
         location = middle;
      }
      else if (list[middle] < item) // not in bottom half
         bottom = middle + 1;
      else                            // item cannot be in top half
         top = middle - 1;
   }
   return location;
}

在我的教科书里，我有这个代码。我想知道为什么我需要 bottom <= top 不仅仅是 !found . 不应该 low 总是变小？所以唯一的决定因素就是！找到了。
谢谢