Design Patterns for Data Structures. Chapter 9. Dictionaries

Transcription

1 Design Patterns for Data Structures Chapter 9 Dictionaries

2 Design Patterns for Data Structures Chapter 9 The key-value pair A dictionary provides storage based on the key retrieval based on the key access to the value associated with a key

3 Design Patterns for Data Structures Chapter 9

4 Design Patterns for Data Structures Chapter 9 dp4dsdistribution projects

5 ADictionary + ~ADictionary( ) + clear( ) + insert(key: K const &, val: V const &) + remove(key: K const &, val: V &): bool + contains(key: K const &, val: V &): bool + tostream(os: ostream &) DictionaryA _data: ArrayP< DictPair<> *> * _size:int + DictionaryA(cap: int) DictionaryBST _tree: BiTreeCSV< DictPair<> > * + DictionaryBST( ) DictionaryL _list: ListCSV< DictPair<> > * + DictionaryL( ) DictionaryHash _hashtable: ArrayP< ListCSV< DictPair<> > *> * _hashfunction: HashFunction + DictionaryHash(cap: int, hashfunction: HashFunction) DictPair _key: K _val: V + DictPair(key: K, val: V const &) + key( ): K const & + val( ): V const &

6 Design Patterns for Data Structures Figure 9.1 ADictionary + ~ADictionary( ) + clear( ) + insert(key: K const &, val: V const &) + remove(key: K const &, val: V &): bool + contains(key: K const &, val: V &): bool + tostream(os: ostream &)

7 Design Patterns for Data Structures Figure 9.2 // ========= ADictionary ========= template <class K, class V> class ADictionary { public: virtual ~ADictionary() { ; virtual void clear() = 0; virtual void insert(k const &key, V const &val) = 0; // Post: This dictionary contains key and its associated value, val, // without duplicate keys. virtual bool remove(k const &key, V &val) = 0; // Post: If key is found, then val is the associated value, // and true is returned; otherwise false is returned. // This dictionary does not contain key and its associated value. virtual bool contains(k const &key, V &val) const = 0; // Post: If key is found, then val is the associated value, // and true is returned; otherwise false is returned. ; virtual void tostream(ostream &os) const = 0;

8 Design Patterns for Data Structures Figure 9.2 // ========= operator<< ========= template<class K, class V> ostream &operator<<(ostream &os, const ADictionary<> &rhs) { rhs.tostream(os); return os;

9 Design Patterns for Data Structures Figure tostream(os: ostream &) DictionaryA _data: ArrayP< DictPair<> *> * _size:int + DictionaryA(cap: int) DictionaryBST _tree: BiTreeCSV< DictPair<> > * + DictionaryBST( ) DictionaryL _list: ListCSV< DictPair<> > * + DictionaryL( ) DictionaryHash _hashtable: ArrayP< ListCSV< DictPair<> > *> * _hashfunction: HashFunction + DictionaryHash(cap: int, hashfunction: HashFunction) DictPair _key: K _val: V + DictPair(key: K, val: V const &) + key( ): K const & + val( ): V const &

10 Design Patterns for Data Structures Figure 9.3 // ========= DictPair ========= template <class K, class V> class DictPair { // Pre: K and V have default constructor, copy constructor, // operator=, operator<<. // K has comparison operators for searching. private: K _key; V _val; public: DictPair(K key, V const &val) : _key(key), _val(val) { K const &key() const { return _key; ; V const &val() const { return _val;

11 Design Patterns for Data Structures Figure 9.3 // ========= DictPair ========= template <class K, class V> class DictPair { // Pre: K and V have default constructor, copy constructor, // operator=, operator<<. // K has comparison operators for searching. private: K _key; V _val; public: DictPair(K key, V const &val) : _key(key), _val(val) { K const &key() const { return _key; ; V const &val() const { return _val;

12 Design Patterns for Data Structures Figure 9.3 // ========= operator<< ========= template <class K, class V> ostream &operator<<(ostream &os, DictPair<> const &rhs) { os << < << rhs.key() <<, << rhs.val() << > ; return os;