CMSC 341

1
CMSC 341
2
List.H

• template ltclass Objectgt
• class List
• public
• List()
• List(const List rhs)
• List()
• const List operator(const List rhs)
• Bool isEmpty() const
• void makeEmpty()
• void remove (const Object x)
• void insert (const Object x,
• const ListIterltObjectgt p)

3
List.H (cont)

• ListIterltObjectgt first()const
• ListIterltObjectgt zeroth()const
• ListIterltObjectgt find(const Object x)
• ListIterltObjectgt findPrevious(const Object x)
• private
• ListNodeltObjectgt header

4
ListNode.H

• template ltclass Objectgt
• class ListNode
• ListNode(const Object theElementObject(),
• ListNode n NULL)
• element(theElement), next(n)
• Object element
• ListNode next
• friend class ListltObjectgt
• friend class ListItrltObjectgt

5
ListItr.H

• template ltclass Objectgt
• class ListItr
• public
• ListItr()current(NULL)
• bool isPastEnd() const return current NULL
• void advance()
• if (!isPastEnd()) current current-gtnext
• const Object retrieve() const
• if (isPastEnd()) throw BadIterator()
• return current-gtelement
• private
• ListNodeltObjectgt current
• ListItr(ListNodeltObjectgt theNode)current(theNod
  e)
• friend class ListltObjectgt

6
Linked List Implementation

• template ltclass Objectgt
• ListltObjectgtList()
• header new ListNodeltObjectgt
• template ltclass Objectgt
• ListltObjectgtisEmpty()
• return !(header-gtnext)

7
Linked List Implementation (cont)

• template ltclass Objectgt
• ListItrltObjectgt ListltObjectgtzeroth()
• return ListItrltObjectgt(header)
• template ltclass Objectgt
• ListItrltObjectgt ListltObjectgtfirst()
• return ListItrltObjectgt(header-gtnext)

8
Linked List Implementation (cont)

• template ltclass Objectgt
• void ListltObjectgt
• insert(const Object x, const ListItrltObjectgt p)
• if (!p.isPastEnd()) //text uses p.current!NULL
• p.current-gtnext
• new ListNodeltObjectgt(x,p.current-gtnext)

9
Linked List Implementation (cont)

• template ltclass Objectgt
• ListItrltObjectgt ListltObjectgt
• find(const Object x const)
• ListNodeltObjectgt p header-gtnext
• while (p!NULL p-gtelement !x)
• p p-gtnext
• return ListItrltObjectgt(p)

10
Linked List Implementation (cont)

• template ltclass Objectgt
• ListItrltObjectgt ListltObjectgt
• findPrevious(const Object x const)
• ListNodeltObjectgt p header
• while (p-gtnext!NULL p-gtnext-gtelement !x)
• p p-gtnext
• return ListItrltObjectgt(p)

11
Linked List Implementation (cont)

• template ltclass Objectgt
• void ListltObjectgt
• remove(const Object x)
• ListItrltObjectgt pfindPrevious(x)
• if (p.current-gtnext ! NULL)
• ListNodeltObjectgt oldnode
• p.current-gtnext
• p.current-gtnext p.current-gtnext-gtnext
• delete oldnode

12
Linked List Implementation (cont)

• template ltclass Objectgt
• void ListltObjectgtmakeEmpty()
• while (!isEmpty()) remove (first().retrieve())

13
Linked List Implementation (cont)

• template ltclass Objectgt
• void ListltObjectgtList()
• makeEmpty() //deletes all nodes except header
• delete header

14
Linked List Implementation (cont)

• template ltclass Objectgt
• const ListltObjectgt ListltObjectgt
• operator (const ListltObjectgt rhs)
• if (this ! rhs)
• makeEmpty()
• ListItrltObjectgt ritr rhs.first()
• ListItrltObjectgt itr zeroth()
• while (!ritr.isPastEnd())
• insert(ritr.retrieve(), itr)
• ritr.advance()
• itr.advance()
• return this