qintdict.3qt man page

QIntDict — Template class that provides a dictionary based on long keys

Synopsis

#include <qintdict.h>

Inherits QPtrCollection.

Public Members

QIntDict ( int size = 17 )

QIntDict ( const QIntDict<type> & dict )

~QIntDict ()

QIntDict<type> & operator= ( const QIntDict<type> & dict )

virtual uint count () const

uint size () const

bool isEmpty () const

void insert ( long key, const type * item )

void replace ( long key, const type * item )

bool remove ( long key )

type * take ( long key )

type * find ( long key ) const

type * operator[] ( long key ) const

virtual void clear ()

void resize ( uint newsize )

void statistics () const

Important Inherited Members

bool autoDelete () const

void setAutoDelete ( bool enable )

Protected Members

virtual QDataStream & read ( QDataStream & s, QPtrCollection::Item & item )

virtual QDataStream & write ( QDataStream & s, QPtrCollection::Item ) const

Description

The QIntDict class is a template class that provides a dictionary based on long keys.

QMap is an STL-compatible alternative to this class.

QIntDict is implemented as a template class. Define a template instance QIntDict<X> to create a dictionary that operates on pointers to X (X*).

A dictionary is a collection of key-value pairs. The key is an long used for insertion, removal and lookup. The value is a pointer. Dictionaries provide very fast insertion and lookup.

Example:

QIntDict<QLineEdit> fields; // long int keys, QLineEdit* values

for ( int i = 0; i < 3; i++ )

    fields.insert( i, new QLineEdit( this ) );

fields[0]->setText( "Homer" );

fields[1]->setText( "Simpson" );

fields[2]->setText( "45" );

QIntDictIterator<QLineEdit> it( fields );

for ( ; it.current(); ++it )

    cout << it.currentKey() << ": " << it.current()->text() << endl;

for ( int i = 0; i < 3; i++ )

    cout << fields[i]->text() << " "; // Prints "Homer Simpson 45"

cout << endl;

fields.remove( 1 ); // Does not delete the line edit

for ( int i = 0; i < 3; i++ )

    if ( fields[i] )

        cout << fields[i]->text() << " "; // Prints "Homer 45"

See QDict for full details, including the choice of dictionary size, and how deletions are handled.

See also QIntDictIterator, QDict, QAsciiDict, QPtrDict, Collection Classes, Collection Classes, and Non-GUI Classes.

QIntDict::QIntDict ( int size = 17 )

Constructs a dictionary using an internal hash array of size size.

Setting size to a suitably large prime number (equal to or greater than the expected number of entries) makes the hash distribution better which leads to faster lookup.

QIntDict::QIntDict ( const QIntDict<type> & dict )

Constructs a copy of dict.

Each item in dict is inserted into this dictionary. Only the pointers are copied (shallow copy).

QIntDict::~QIntDict ()

Removes all items from the dictionary and destroys it.

All iterators that access this dictionary will be reset.

See also setAutoDelete().

bool QPtrCollection::autoDelete () const

Returns the setting of the auto-delete option. The default is FALSE.

See also setAutoDelete().

void QIntDict::clear () [virtual]

Removes all items from the dictionary.

The removed items are deleted if auto-deletion is enabled.

All dictionary iterators that access this dictionary will be reset.

See also remove(), take(), and setAutoDelete().

Reimplemented from QPtrCollection.

uint QIntDict::count () const [virtual]

Returns the number of items in the dictionary.

See also isEmpty().

Reimplemented from QPtrCollection.

type * QIntDict::find ( long key ) const

Returns the item associated with key, or 0 if the key does not exist in the dictionary.

If there are two or more items with equal keys, then the most recently inserted item will be found.

Equivalent to operator[].

See also operator[]().

Example: table/bigtable/main.cpp.

void QIntDict::insert ( long key, const type * item )

Insert item item into the dictionary using key key.

Multiple items can have the same key, in which case only the last item will be accessible using operator[]().

item may not be 0.

See also replace().

Example: scribble/scribble.cpp.

bool QIntDict::isEmpty () const

Returns TRUE if the dictionary is empty; otherwise returns FALSE.

See also count().

QIntDict<type> & QIntDict::operator= ( const QIntDict<type> & dict )

Assigns dict to this dictionary and returns a reference to this dictionary.

This dictionary is first cleared and then each item in dict is inserted into this dictionary. Only the pointers are copied (shallow copy), unless newItem() has been reimplemented.

type * QIntDict::operator[] ( long key ) const

Returns the item associated with key, or 0 if the key does not exist in the dictionary.

If there are two or more items with equal keys, then the most recently inserted item will be found.

Equivalent to the find() function.

See also find().

QDataStream & QIntDict::read ( QDataStream & s, QPtrCollection::Item & item ) [virtual protected]

Reads a dictionary item from the stream s and returns a reference to the stream.

The default implementation sets item to 0.

See also write().

bool QIntDict::remove ( long key )

Removes the item associated with key from the dictionary. Returns TRUE if successful, i.e. if the key is in the dictionary; otherwise returns FALSE.

If there are two or more items with equal keys, then the most recently inserted item will be removed.

The removed item is deleted if auto-deletion is enabled.

All dictionary iterators that refer to the removed item will be set to point to the next item in the dictionary's traversal order.

See also take(), clear(), and setAutoDelete().

Example: table/bigtable/main.cpp.

void QIntDict::replace ( long key, const type * item )

If the dictionary has key key, this key's item is replaced with item. If the dictionary doesn't contain key key, item is inserted into the dictionary using key key.

item may not be 0.

Equivalent to:

QIntDict<char> dict;

//      ...

if ( dict.find(key) )

    dict.remove( key );

dict.insert( key, item );

If there are two or more items with equal keys, then the most recently inserted item will be replaced.

See also insert().

Example: table/bigtable/main.cpp.

void QIntDict::resize ( uint newsize )

Changes the size of the hashtable to newsize. The contents of the dictionary are preserved, but all iterators on the dictionary become invalid.

void QPtrCollection::setAutoDelete ( bool enable )

Sets the collection to auto-delete its contents if enable is TRUE and to never delete them if enable is FALSE.

If auto-deleting is turned on, all the items in a collection are deleted when the collection itself is deleted. This is convenient if the collection has the only pointer to the items.

The default setting is FALSE, for safety. If you turn it on, be careful about copying the collection - you might find yourself with two collections deleting the same items.

Note that the auto-delete setting may also affect other functions in subclasses. For example, a subclass that has a remove() function will remove the item from its data structure, and if auto-delete is enabled, will also delete the item.

See also autoDelete().

Examples:

uint QIntDict::size () const

Returns the size of the internal hash array (as specified in the constructor).

See also count().

void QIntDict::statistics () const

Debugging-only function that prints out the dictionary distribution using qDebug().

type * QIntDict::take ( long key )

Takes the item associated with key out of the dictionary without deleting it (even if auto-deletion is enabled).

If there are two or more items with equal keys, then the most recently inserted item will be taken.

Returns a pointer to the item taken out, or 0 if the key does not exist in the dictionary.

All dictionary iterators that refer to the taken item will be set to point to the next item in the dictionary's traversing order.

See also remove(), clear(), and setAutoDelete().

Example: table/bigtable/main.cpp.

QDataStream & QIntDict::write ( QDataStream & s, QPtrCollection::Item ) const [virtual protected]

Writes a dictionary item to the stream s and returns a reference to the stream.

See also read().

See Also

http://doc.trolltech.com/qintdict.html http://www.trolltech.com/faq/tech.html

Author

Generated automatically from the source code.

Bugs

If you find a bug in Qt, please report it as described in http://doc.trolltech.com/bughowto.html. Good bug reports help us to help you. Thank you.

The definitive Qt documentation is provided in HTML format; it is located at $QTDIR/doc/html and can be read using Qt Assistant or with a web browser. This man page is provided as a convenience for those users who prefer man pages, although this format is not officially supported by Trolltech.

If you find errors in this manual page, please report them to qt-bugs@trolltech.com. Please include the name of the manual page (qintdict.3qt) and the Qt version (3.3.8).

Referenced By

QIntDict.3qt(3) is an alias of qintdict.3qt(3).

2 February 2007 Trolltech AS