1. Containers and the Standard Template Library (STL)
Professor Hugh C. Lauer CS-2303, System Programming Concepts
(Slides include materials from The C Programming Language, 2nd edition, by Kernighan and Ritchie, Absolute C++, by Walter Savitch, The C++ Programming Language, Special Edition, by Bjarne Stroustrup, and from C: How to Program, 5th and 6th editions, by Deitel and Deitel)
CS-2303, A-Term 2012
Containers

2. From previous topic
class BinaryTree { public: TreeNode *AddNode(const string &word); int getTotalNodes(); void PrintTree(ostream &output); BinaryTree(); //Default constructor ~BinaryTree(); //Destructor private: static int totalNodes; void PrintTree(TreeNode *subtree, ostream &output); TreeNode *AddNode(TreeNode *subtree, const string &word); TreeNode *root; }; // class BinaryTree
There is something else unsatisfying about this implementation.
What is it?
CS-2303, A-Term 2012
Containers

3. From previous topic
class BinaryTree { public: TreeNode *AddNode(const string &word); int getTotalNodes(); void PrintTree(ostream &output); BinaryTree(); //Default constructor ~BinaryTree(); //Destructor private: static int totalNodes; void PrintTree(TreeNode *subtree, ostream &output); TreeNode *AddNode(TreeNode *subtree, const string &word); TreeNode *root; }; // class BinaryTree
The class TreeNode is also problem specific — it has a string and a count
CS-2303, A-Term 2012
Containers

4. Consequence
It would be a fair amount of work to adapt this binary tree implementation to some other purpose
E.g., managing parse trees in a language translator
Managing employee records
Keeping track of baseball statistics
...
It would be nice to have a binary tree class that would work for a wide variety of payload types
CS-2303, A-Term 2012
Containers

5. Templates to the rescue!
template <class T> class TreeNode { public: friend class BinaryTree<T> friend class iterator<T> TreeNode(T data) : payload(data) {} private: T payload; TreeNode<T> *left; TreeNode<T> *right; } // template <class T> // class TreeNode
template <class T> class BinaryTree { public: void insert(T item); TreeNode<T> *find(T item); … // iterator methods? private: TreeNode<T> * root; void insert(T item, TreeNode<T> *subtree); TreeNode<T> *find(T item, TreeNode<T> *subtree); } // template <class T> // class BinaryTree
CS-2303, A-Term 2012
Containers

6. See Absolute C++ §17.4 & Figs 17.36 – 17.38
Result
You can concentrate on building the binary tree
Without worrying much about what it contains
You can hand off the task of comparing nodes to the overloaded operators of <class T>
You can take advantage of decades of knowledge and expertise accumulated about binary trees
… and other forms of search trees …
See Absolute C++ §17.4 & Figs – 17.38
CS-2303, A-Term 2012
Containers

7. The Standard Template Library (STL)
A large collection of template container classes
Also a bunch of other stuff
Part of the C++ standard
Embodies the collective wisdom and experience of the contributors
CS-2303, A-Term 2012
Containers

8. Containers in the STL Vectors vector<bool>
Generalization of arrays
Range checking
Resizable
All common C operators are overloaded to apply to vectors
++, --, [], ->, *, etc.
Comprehensive set of iterators
vector<bool>
A highly optimized specialization of one-bit per element
CS-2303, A-Term 2012
Containers

9. Containers in the STL (continued)
List
Doubly-linked
Stack
Deque
i.e., a double ended queue
Queue
All of the usual list operations, constrained to circumstances of the container
Iterators specifically adapted to these containers
CS-2303, A-Term 2012
Containers

10. Containers in the STL (continued)
basic_string
The underlying class for string
typedef basic_string<char> string
Comparisons, assignments, iterators, etc.
Substring, searching, pattern-matching
String stream
I.e., using << and >> to insert to or extract from strings instead of streams
International character strings
wchar, unicode, etc.
CS-2303, A-Term 2012
Containers

11. Containers in the STL (continued)
map
Associative array — search by value
set
Sets of objects
Usual set operators for union, intersection, etc.
bitset
Array of booleans
CS-2303, A-Term 2012
Containers

12. Other features in STL General utilities Iterators General algorithms
Date & time, memory allocators, etc.
Iterators
Lots of tools
General algorithms
Mostly for sets, partitions, sequences, binary searches, swapping, sorting, etc.
Exception handling
exception class, assertions, etc.
Localization tools
Representations of dates, currencies, numbers, etc.
Numerics
Numeric operations, complex, math functions, random numbers, etc.
Input-output
Streams, files, manipulators, etc. …
CS-2303, A-Term 2012
Containers

13. Questions?
CS-2303, A-Term 2012
Containers