Generic Positional Containers and Double-Ended Queues

1
Generic Positional Containers and Double-Ended
Queues

• Andy Wang
• Data Structures, Algorithms, and Generic
  Programming

2
Generic Positional Containers

• A generic container C
• Stores elements by position
• vectori a
• list.insert(I, a)
• A template class for a proper type T
• CltTgt is a proper type
• CltTgt is capable of storing a number of T objs
• CltTgt supports an iterater class CltTgtIterator

3
More on Generic pContainers

• Organized and accessed by position
• Can insert any T object at any position in CltTgt
• Can remove any T object at any position in CltTgt
• Can support
• PushFront(), PopFront(), Front()
• PushBack(), PopBack(), Back()

4
Traditional Double-Ended Queue Class

• Deque (pronounced deck)
• Deque operations
• Push/Pop at either end
• Retrieve data from either end
• Proper type

5
Traditional Double-Ended Queue Class (2)

• Assumptions on element type T (proper type)
• Constructor T() and destructor T()
• Copy constructor
• Assignment operator

6
Specifying TDequeltTgt

• Traditional assumptions, plus
• O(1) average runtime, O(Size()) space
• PushFront(t), PopFront(), Front()
• PushBack(t), PopBack(), Back()
• O(1) time and space for iterator opeartions
• Random access iterators (, pointer arithmetics)

7
TDequeltTgt Implementation Plan

• Circular array
• Protected array content of size content_size
• Illusion contentcontent_size content0

8
TDequeltTgt D Illustrated

• content_size 8
• D.Empty() true

0 1 2 3 4 5 6 7

content
9
TDequeltchargt D Illustrated (2)

• content_size 8
• D.PushBack(M)

0 1 2 3 4 5 6 7
M
content
10
TDequeltchargt D Illustrated (3)

• content_size 8
• D.PushBack(e)

0 1 2 3 4 5 6 7
M e
content
11
TDequeltchargt D Illustrated (4)

• content_size 8
• D.PushBack(r)

0 1 2 3 4 5 6 7
M e r
content
12
TDequeltchargt D Illustrated (5)

• content_size 8
• D.PushBack(r)

0 1 2 3 4 5 6 7
M e r r
content
13
TDequeltchargt D Illustrated (6)

• content_size 8
• D.PushBack(y)

0 1 2 3 4 5 6 7
M e r r y
content
14
TDequeltchargt D Illustrated (7)

• content_size 8
• D.PopFront()
• O(1)

0 1 2 3 4 5 6 7
e r r y
content
15
TDequeltchargt D Illustrated (8)

• content_size 8
• D.PopFront()

0 1 2 3 4 5 6 7
r r y
content
16
TDequeltchargt D Illustrated (9)

• content_size 8
• D.PushBack(G)

0 1 2 3 4 5 6 7
r r y G
content
17
TDequeltchargt D Illustrated (10)

• content_size 8
• D.PushBack(o)
• D.Size() (7 2 8) 8

0 1 2 3 4 5 6 7
r r y G o
content
18
TDequeltchargt D Illustrated (11)

• content_size 8
• D.PushBack(A)
• D.Size() (0 2 8) 8

0 1 2 3 4 5 6 7
r r y G o A
content
19
TDequeltchargt D Illustrated (12)

• content_size 8
• D.PushBack(r)

0 1 2 3 4 5 6 7
r r r y G o A
content
20
TDequeltchargt D Illustrated (13)

• D.Size() content_size 1
• Return full or
• Double the capacity

0 1 2 3 4 5 6 7
r r r y G o A
content
21
TDequeltTgt Implementation Plan (2)

• Relative Indexing
• Protected integers begin, end
• Element position relative to begin
• Front element is contentbegin
• Back element is contentend 1
• Size is (end begin content_size)
  content_size

22
TDequeltTgt Implementation Plan (3)

• Class Bracket Operator
• Similar to TVector
• Distinguished from TDeque Iterator bracket
  operation

23
TDequeltTgtIterator Implementation Plan

• Public interface
• Start with the public interface of
  TListltTgtIterator
• Add bracket operator
• Add pointer arithmetic
• Protected data
• Pointer to a specific TDequeltTgt object
• A deque index value

24
Defining TDequeltTgt

• template lttypename Tgt
• class TDeque
• public
• typedef T value_type // type definitions
• typedef TDequeIteratorltTgt Iterator
• TDeque() // constructors and deconstructor
• TDeque(size_t, const T)
• TDeque(const TDequeltTgt)
• TDeque()
• // display functions
• void Display(ostream os, char ofc \0)
  const
• void Dump(ostream os) const

25
Defining TDequeltTgt (2)

• int Empty() const // container read-only
  routines
• size_t Size() const
• T Front() const
• T Back() const
• T operator (size_t) const
• int PushFront(const T) // container write
  routines
• int PopFront()
• int PushBack(const T)
• int PopBack()
• TDequeltTgt operator(const TDequeltTgt)

26
Defining TDequeltTgt (3)

• friend class TDequeIteratorltTgt // iterator
  support
• Iterator Begin() const
• Iterator End() const
• protected
• T content
• size_t content_size, begin, end

27
Defining TDequeltTgt (4)

• // operator overloads (friend status not
  required)
• templateltclass Tgt
• ostream operatorltlt(ostream os, const TDequeltTgt
  a)
• templateltclass Tgt
• int operator(const TDequeltTgt, const
  TDequeltTgt)
• templateltclass Tgt
• int operator!(const TDequeltTgt, const
  TDequeltTgt)

28
Defining TDequeIteratorltTgt

• template lttypename Tgt
• class TDequeIterator
• friend class TDequeltTgt
• public
• typedef T value_type // terminology support
• TDequeIterator() // constructors
• TDequeIterator(const TDequeltTgt I)
• TDequeIterator(const TDequeIteratorltTgt I)
• TDequeIterator(const size_t i)
• T Retrieve() const // return ptr to current
  Tval
• int Valid() const // cursor is valid element

29
Defining TDequeIteratorltTgt (2)

• // various operators
• int operator(const TDequeIteratorltTgt I2)
  const
• int operator!(const TDequeIteratorltTgt I2)
  const
• T operator() const // return reference to
  current Tval
• T operator (size_t i) const // return ref
  to Tval at index
• TDequeIteratorltTgt operator(const
  TDequeIteratorltTgt I)
• TDequeIteratorltTgt operator() // prefix
• TDequeIteratorltTgt operator(int) // postfix
• TDequeIteratorltTgt operator--() // prefix
• TDequeIteratorltTgt operator--(int) // postfix

30
Defining TDequeIteratorltTgt (3)

• // pointer arithmetic
• long operator-(const TDequeIteratorltTgt I2)
  const
• TDequeIteratorltTgt operator(long n)
• TDequeIteratorltTgt operator-(long n)
• TDequeIteratorltTgt operator(long n) const
• TDequeIteratorltTgt operator(int n)
• TDequeIteratorltTgt operator-(int n)
• TDequeIteratorltTgt operator(int n) const
• TDequeIteratorltTgt operator(unsigned long n)
• TDequeIteratorltTgt operator-(unsigned long n)
• TDequeIteratorltTgt operator(unsigned long n)
  const
• TDequeIteratorltTgt operator(unsigned int n)
• TDequeIteratorltTgt operator-(unsigned int n)
• TDequeIteratorltTgt operator(unsigned int n)
  const

31
Defining TDequeIteratorltTgt (3)

• protected
• const TDequeltTgt Qptr
• size_t index

32
Implementing TDequeltTgt

• Default constructor
• template lttypename Tgt
• TDequeltTgtTDeque() content(0), begin(0),
  end(0), content_size(0)
• content new Tdefault_content_size
• if (content 0)
• // error
• content_size default_content_size

33
Implementing TDequeltTgt (2)

• Copy constructor
• template lttypename Tgt
• TDequeltTgtTDeque(const TDequeltTgt Q)
  content_size(Q.content_size), begin(Q.begin),
  end(Q.end)
• content new Tcontent_size
• if (content 0)
• // error
• for (size_t j 0 j lt content_size j)
• contentj Q.contentj

34
Implementing TDequeltTgt (3)

• Read-only functions
• template lttypename Tgt
• size_t TDequeltTgtSize() const
• return (end begin content_size)
  content_size
• template lttypename Tgt
• T TDequeltTgtoperator (size_t i) const
• if (Size() lt i)
• // error
• return (i begin) content_size

35
Implementing TDequeltTgt (4)

• Display functions
• template lttypename Tgt
• void TDequeltTgtDisplay(ostream os, char ofc)
  const
• for (size_t j 0 j lt Size() j)
• os ltlt operator(j)
• if (ofc ! \0)
• os ltlt ofc
• template lttypename Tgt
• void TDequeltTgtDump(ostream os) const
• for (size_t j 0 j lt content_size j) //
  print

36
Implementing TDequeltTgt (5)

• Read-only operator overloads
• template lttypename Tgt
• ostream operatorltlt(ostream os, const TDequeltTgt
  Q)
• Q.Display(os)
• return(os)
• template lttypename Tgt
• int operator(const TDequeltTgt Q1, const
  TDequeltTgt Q2)
• if (Q1.Size() ! Q2.Size()) return 0
• for (size_t j 0 j lt Q1.Size() j)
• if (Q1j ! Q2j) return 0
• return 1

37
Implementing TDequeltTgt (6)

• Read-only operator overloads
• template lttypename Tgt
• int operator!(const TDequeltTgt Q1, const
  TDequeltTgt Q2)
• return !(Q1 Q2)

38
Implementing TDequeltTgt (7)

• Read-only functions
• template lttypename Tgt
• int TDequeltTgtEmpty() const
• return begin end
• template lttypename Tgt
• void TDequeltTgtClear()
• begin end 0

39
Implementing TDequeltTgt (8)

• Read-only functions
• template lttypename Tgt
• T TDequeltTgtFront() const
• // check for empty TDeque
• return contentbegin
• template lttypename Tgt
• T TDequeltTgtBack() const
• // check for empty TDeque
• return (end 1 content_size) content_size

40
Implementing TDequeltTgt (9)

• Iterator support
• template lttypename Tgt
• TDequeIteratorltTgt TDequeltTgtBegin() const
• TDequeltTgtIterator I
• I.Qptr this
• I.index 0
• return I
• template lttypename Tgt
• TDequeIteratorltTgt TDequeltTgtEnd() const
• TDequeltTgtIterator I
• I.Qptr this
• I.index Size()
• return I

41
Implementing TDequeltTgt (10)

• Assignment
• template lttypename Tgt
• TDequeltTgt TDequeltTgtoperator(const TDequeltTgt
  Q)
• if (this ! Q)
• T newcontent new TQ.content_size
• // check for allocation
• delete content
• content newcontent
• content_size Q.content_size
• begin Q.begin
• end Q.end
• // copy queue elements
• return this

42
Implementing TDequeltTgt (11)

• PushBack
• template lttypename Tgt
• int TDequeltTgtPushBack(const T Tval)
• if (Size() 1 gt content_size) // deque is
  full
• unsigned j, k
• size_t newcontent_size 2 content_size
• if (content_size 0) newcontent_size 2
• T newcontent new Tnewcontent_size
• // check for allocation error
• for (j k begin
• j ! end
• j (j 1) content_size, k)
• newcontentk contentj

43
Implementing TDequeltTgt (12)

• PushBack
• if (begin lt end) begin content_size
• delete content
• content newcontent
• content_size newcontent_size
• contentend Tval
• end (end 1) content_size
• return 1

44
Implementing TDequeltTgt (13)

• PushFront
• template lttypename Tgt
• int TDequeltTgtPushFront(const T Tval)
• if (Size() 1 gt content_size) // deque is
  full
• unsigned j, k
• size_t newcontent_size 2 content_size
• if (content_size 0) newcontent_size 2
• T newcontent new Tnewcontent_size
• // check for allocation error
• for (j k begin
• j ! end
• j (j 1) content_size, k)
• newcontentk contentj

45
Implementing TDequeltTgt (14)

• PushFront
• if (begin lt end) begin content_size
• delete content
• content newcontent
• content_size newcontent_size
• begin (begin 1 content_size)
  content_size
• contentbegin Tval
• return 1

46
Implementing TDequeltTgt (15)

• Pop routines
• template lttypename Tgt
• int TDequeltTgtPopFront()
• if (begin end) return 0
• begin (begin 1) content_size
• return 1
• template lttypename Tgt
• int TDequeltTgtPopBack()
• if (begin end) return 0
• end (end 1 content_size) content_size
• return 1

47
Implementing TDequeIteratorltTgt

• Constructors
• template lttypename Tgt
• TDequeIteratorltTgtTDequeIterator() Qptr(0),
  index(0)
• template lttypename Tgt
• TDequeIteratorltTgtTDequeIterator(const
  TDequeltTgt Q) Qptr(Q), index(0)
• template lttypename Tgt
• TDequeIteratorltTgtTDequeIterator(const
  TDequeIteratorltTgt I) Qptr(I.Qptr),
  index(I.index)

48
Implementing TDequeIteratorltTgt (2)

• Initialization routines
• template lttypename Tgt
• void TDequeIteratorltTgtInitialize(const
  TDequeltTgt Q)
• Qptr Q
• index 0
• template lttypename Tgt
• void TDequeIteratorltTgtrInitialize(const
  TDequeltTgt Q)
• Qptr Q
• index Q.Size() 1

49
Implementing TDequeIteratorltTgt (3)

• Helper functions
• template lttypename Tgt
• int TDequeIteratorltTgtValid() const
• if (Qptr 0) return 0
• if (index gt Qptr-gtSize()) return 0
• return 1
• template lttypename Tgt
• T TDequeIteratorltTgtoperator (size_t i) const
  
• if (!Qptr) // error
• return Qptr-gtoperator(index i)

50
Implementing TDequeIteratorltTgt (4)

• Helper functions
• template lttypename Tgt
• T TDequeIteratorltTgtRetrieve() const
• // check for validity
• return Qptr-gtoperator(index)
• template lttypename Tgt
• T TDequeIteratorltTgtoperator () const
• if (Qptr 0) // error
• if (Qptr-gtSize() 0) // error
• return Qptr-gtoperator(index)

51
Implementing TDequeIteratorltTgt (5)

• Comparators
• template lttypename Tgt
• int TDequeIteratorltTgtoperator(const
  TDequeIteratorltTgt I2) const
• if (Qptr ! I2.Qptr) return 0
• if (index ! I2.index) return 0
• return 1
• template lttypename Tgt
• int TDequeIteratorltTgtoperator!(const
  TDequeIteratorltTgt I2) const
• return !(this I2)

52
Implementing TDequeIteratorltTgt (6)

• Assignment
• template lttypename Tgt
• TDequeIteratorltTgt TDequeIteratorltTgtoperator(co
  nst TDequeIteratorltTgt I)
• if (this ! I)
• Qptr I.Qptr
• index I.index
• return this

53
Implementing TDequeIteratorltTgt (7)

• Various operators
• template lttypename Tgt
• TDequeIteratorltTgt TDequeIteratorltTgtoperator()
  
• index
• return this
• template lttypename Tgt
• TDequeIteratorltTgt TDequeIteratorltTgtoperator(in
  t)
• TDequeIteratorltTgt I(this)
• operator ()
• return I

54
Implementing TDequeIteratorltTgt (8)

• Various operators
• template lttypename Tgt
• TDequeIteratorltTgt TDequeIteratorltTgtoperator--()
  
• --index
• return this
• template lttypename Tgt
• TDequeIteratorltTgt TDequeIteratorltTgtoperator--(in
  t)
• TDequeIteratorltTgt I(this)
• operator --()
• return I

55
Implementing TDequeIteratorltTgt (9)

• Various operators
• template lttypename Tgt
• long TDequeIteratorltTgtoperator-(const
  TDequeIteratorltTgt I2) const
• return index I2.index
• template lttypename Tgt
• TDequeIteratorltTgt TDequeIteratorltTgtoperator(lon
  g n) const
• TDequeIteratorltTgt I(this)
• return I n

56
Implementing TDequeIteratorltTgt (10)

• Various operators
• template lttypename Tgt
• TDequeIteratorltTgt TDequeIteratorltTgtoperator(l
  ong n)
• index n
• return this
• template lttypename Tgt
• TDequeIteratorltTgt TDequeIteratorltTgtoperator-(l
  ong n)
• index - n
• return this