QIntDict

NAME

SYNOPSIS

Inherits QPtrCollection.

Public Members

Important Inherited Members

Protected Members

DESCRIPTION

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.  

MEMBER FUNCTION DOCUMENTATION

QIntDict::QIntDict ( int size = 17 )

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 )

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

QIntDict::~QIntDict ()

All iterators that access this dictionary will be reset.

See also setAutoDelete().  

bool QPtrCollection::autoDelete () const

See also setAutoDelete().  

void QIntDict::clear () [virtual]

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]

See also isEmpty().

Reimplemented from QPtrCollection.  

type * QIntDict::find ( long key ) const

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 )

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

See also count().  

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

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

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]

The default implementation sets item to 0.

See also write().  

bool QIntDict::remove ( long key )

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 )

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 )

void QPtrCollection::setAutoDelete ( bool enable )

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

See also count().  

void QIntDict::statistics () const

type * QIntDict::take ( long key )

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]

See also read().

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