c04p194.txt

来自「Data Abstraction & Problem Solving with 」· 文本 代码 · 共 43 行

void List::retrieve(int index,
                    ListItemType& dataItem) const throw(ListIndexOutOfRangeException)
{
   if ((index < 1) || (index > getLength()))
      throw ListIndexOutOfRangeException(
              "ListIndexOutOfRangeException: retrieve index out of range");
   else
   {  // get pointer to node, then data in node
      ListNode *cur = find(index);
      dataItem = cur->item;
   }  // end if
} // end retrieve

void List::insert(int index, ListItemType newItem) throw(ListIndexOutOfRangeException)
{
   int newLength = getLength() + 1;

   if ((index < 1) || (index > newLength))
      throw ListIndexOutOfRangeException(
              "ListIndexOutOfRangeException: insert index out of range");

   else
   {  // create new node and place newItem in it
      ListNode *newPtr = new ListNode;
      size = newLength;
      newPtr->item = newItem;

      // attach new node to list
      if (index == 1)
      {  // insert new node at beginning of list
         newPtr->next = head;
         head = newPtr;
      }
      else
      {  ListNode *prev = find(index-1);
         // insert new node after node
         // to which prev points
         newPtr->next = prev->next;
         prev->next = newPtr;
      }  // end if
   } // end if
} // end insert