container types sequence containers associative containers adapter classes stack container

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Container TypesSequence ContainersAssociative ContainersAssociative ContainersAdapter ClassesAdapter Classes

Stack ContainerStack ContainerQueue ContainerQueue ContainerPriority Queue ContainerPriority Queue ContainerSet ContainerSet ContainerMap ContainerMap Container

C++ ArraysC++ Arrays

Containers OverviewContainers Overviewand Class Vectorand Class Vector

VectorsVectors

Templated Insertion SortTemplated Insertion Sort

Template ClassesTemplate ClassesStore ClassStore Class

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STLSTL C++ STL provides 10 container classes 4 additional types considered “near-containers”

– array– string– bitset– valarray

Extensions to Standard– slist– rope – huge strings– unordered_set, unordered_map,

unordered_multiset, unordered_multimap

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Container CategoriesContainer Categories

Sequence Containers

Adapter Containers

Associative Containers

Vector Stack Set, Multiset

Deque Queue Map, Multimap

List Priority Queue

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Sequence ContainersSequence Containers

A sequence container stores data by position in linear order 1st element, 2nd element, and so forth

P o s itio n 0 P o s itio n 4P o s itio n 3P o s itio n 2P o s itio n 1

S eq uenc e C o ntainer

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Associative ContainersAssociative Containers Associative containers store elements by key

– Ex: name, SS #, or part number A program accesses an element in an

associative container by its key– May bear no relationship to the location of the

element in the container– Access by key O(lg N)

Implementation?

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Adapter ClassesAdapter Classes Use a sequence container as underlying

storage structure– E.g. Stack and Queue use Deque– Design Pattern: Adapter

Adapter’s interface provides a restricted set of operations from underlying storage structure– How is stack restricted? – queue?

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Stack ContainersStack ContainersA stack allows access at only one end of sequence,

called the top.

C

A top

Push A

BA

top

Push B

Btop

Push C(a)

C

BA

top

Pop C(b)

B

A topPop B

A

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Queue ContainersQueue ContainersA queue is a container that allows access only at front

and back

A B C D

E

B C D E

Aback front

Insert Delete

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Priority Queue ContainersPriority Queue Containerspriority queue -- HPFO

Push elements in any order -- pop operation removes the largest (or smallest) value

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3

13

15

V alue = 8

27

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Set ContainersSet ContainersA set is a collection of unique values, called keys or set

members.

5

3

1

1527

S et A

F o rd

B uic k

H o nd a

S et B

B M W

Jeep

Jaguar

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Map ContainersMap ContainersA map is a storage structure that implements a key-

value relationship.

D 7 B -9 1 6

W 9 1 -A 8 3

4 .9 5

1 2 .5 0

M irage

C allo w ay

A 2 9 -4 6 8

D 7 B -9 1 6

W 9 1 -A 8 3

In d ex Ven d o rP riceP art #

A 2 9 -4 6 8 8 .7 5 M art in

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C++ ArraysC++ ArraysFixed-size collection – homogenous Stores the n (size) elements in contiguous block

arr[0 ] arr[1 ] arr[2 ]

0 1 2 n -1

. . . arr[n -1 ]

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Evaluating an Array as a Evaluating an Array as a ContainerContainer

Size is fixed at the time of its declaration– Does an array know its size?

C++ arrays do not allow the assignment of one array to another– Requires loop structure with the array size as an

upper bound– *or* what algorithm?

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VectorsVectors

v [ 0 ] v [ 1 ] v [ 2 ] . . . v [ n-1 ] ro o m to gro w

0 1 2 n-1

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CLASS vector Constructors <vector>

vector ();Create an empty vector. Default.

 vector (size_type n, const T& value = T ());

Create a vector with n elements equal to “value”. If the value argument is omitted, the elements are filled with the default value for type T. Type T must have a default constructor, and the default value of type T is specified by the notation T ().

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CLASS vector Constructors <vector>

vector (InputIter first, InputIter last);Initialize the vector using the range [first, last).

first and last are input iterators (can be read).

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CLASS vector Operations <vector>

T& back ();Return the value of the item at the rear of the vector.

Precondition: The vector must contain at least one element.

 const T& back () const;

Constant version of back().  

bool empty () const;Return true if the vector is empty and false

otherwise.

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CLASS vector Operations <vector>

T& operator[ ] (size_type i);Allow the vector element at index i to be retrieved or

modified.Precondition: The index, i, must be in the range 0

i < n, where n is the number of elements in the vector.

Postcondition: If the operator appears on the left side of an assignment statement, the expression on the right side

modifies the element referenced by the index.  

const T& operator[ ] (size_type i) const;Constant version of the index operator.

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CLASS vector Operations <vector>

void push_back (const T& value);Add a value at the rear of the vector.

Postcondition: The vector has a new element at the rear and its size increases by 1.

 void pop_back ();

Remove the item at the rear of the vector.Precondition: The vector is not empty.Postcondition: The vector has a new element at

the rear or is empty.

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CLASS vector Operations <vector>

iterator erase (iterator pos);Erase the element pointed to by pos.Precondition: The vector is not empty.Postcondition: The vector has one fewer element.

iterator erase (iterator first, iterator last);Erase all elements within the iterator range [first,

last).Precondition: The vector is not empty.Postcondition: The size decreases by the

number of elements in the range.

Both invalidate iterators beyond range erased.

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CLASS vector Operations <vector>

iterator insert (iterator pos, const T& value);Insert value before pos, and return an iterator pointing to the position of the new value in the vector. The

operation invalidates any existing iterators beyond pos.Postcondition: The list has a new element.

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CLASS vector Operations <vector>

void resize (size_type n, const T& fill = T());Modify the size of the vector. If the size is increased,

the value fill is added to the elements on the tail of the vector. If the size is decreased, the original

values at the front are retained.Postcondition: The vector has size n.

 void reserve (size_type n);

Only will increase capacity. Postcondition: capacity () >= n

size_type size () const;Return the number of elements in the vector.

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Output with VectorsOutput with Vectorstemplate <typename T>void writeVector (const vector<T>& v){// capture the size of the vector in nsize_t i, n = v.size ();for (i = 0; i < n; ++i)cout << v[i] << " ";

cout << endl;}

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Declaring Vector ObjectsDeclaring Vector Objects// vector of size 5 containing the integer // value 2vector<int> intVector (5, 2);

// vector of size 10; each element // contains the empty string vector<string> strVector (10);

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Adding and Removing Adding and Removing Vector ElementsVector Elements

12 -5 8 1412 -5 8 140

Before

v.size() == 4

43210321

v.size() == 5

After v.push_back (10)

10

4.64.6 6.8

0Before

v.size() == 2

01

v.size() == 1

After v.pop_back ()

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Resizing a VectorResizing a Vectorint arr[5] = {7, 4, 9, 3, 1};vector<int> v (arr, arr + 5);// v initially has 5 integersv.resize (10);// size is doubledv.resize (4); // vector contracted; data

// is lost

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Insertion SortInsertion Sort Can use with vector’s or arrays Count comparisons Best-case run time?– T(N) = N - 1 = O(N) Worst-case?

1

1

)(Nj

j

jNT

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Insertion Sort AlgorithmInsertion Sort Algorithm// sort a vector of type T using insertion // sorttemplate <typename T>void insertionSort (vector<T>& v){// Place v[i] into the sublist v[0] ... //

v[i-1], 1 <= i < n, so it is in the // correct position

size_t n = v.size ();

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Insertion Sort AlgorithmInsertion Sort Algorithmfor (size_t i = 1; i < n; ++i)

{ // Index j scans down list from v[i] // looking for correct position to // locate target. Assigns it to v[j]

size_t j = i; T temp = v[i]; // Locate insertion point by scanning

// downward as long as temp < v[j-1] // and we have not encountered the // beginning of the list

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Insertion Sort AlgorithmInsertion Sort Algorithmwhile (j > 0 && temp < v[j-1])

{ // Shift elements up list to make // room for insertion

v[j] = v[j-1]; --j; } // Location is found; insert temp v[j] = temp; }}

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Class TemplatesClass Templates Can templatize classes as well as functions All container classes in STL are templates Syntaxtemplate <typename T1,

typename T2, … >class ClassName { … } Concrete Store <T> template example

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template <typename T>class Store {public:

// Ctor: init w/item or default TStore (const T& item = T())

: m_value (item) { }

  T getValue () const { return m_value;

}

Class Template StoreClass Template Store

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void setValue (const T& item) {m_value = item;

} private:T m_value;

};

Use:Store<double> s;s.setValue (4.3);

Class Template Store (Cont’d)Class Template Store (Cont’d)