c08p432.txt

来自「Data Abstraction & Problem Solving with 」· 文本 代码 · 共 40 行

#include "ListI.h"
ListIterator List:: begin() const
{
   ListIterator iter(this, head);
   return iter;
}  // end begin

ListIterator List::end() const
{
   ListIterator iter(this, NULL);
   return iter;
}  // end end

ListIterator List::insert(ListIterator iter, 
                          ListItemType newItem)
                    throw(ListException)
{ // Make sure iterator references this list
   if ((iter.container == this))
   {  // create new node and place NewItem in it
      ListNode *newPtr = new ListNode(newItem, NULL);
      size++;
      // attach new node to list
      if (iter == begin())
      {  // insert new node at beginning of list
         newPtr->next = head;
         head = newPtr;
      }
      else
      {  ListNode *prev = findPrev(iter);
         // insert new node before node 
         // to which iter references
         newPtr->next = prev->next;
         prev->next = newPtr;
      }  // end if
      
      return ListIterator(this, newPtr);
   }
   else
      throw ListException("ListException: insert has bad iterator value");
} // end insert