Q3PtrDict Class Reference
[Qt3Support module]

Detailed Description

The Q3PtrDict class is a template class that provides a dictionary based on void* keys.

Q3PtrDict is implemented as a template class. Define a template instance Q3PtrDict<X> to create a dictionary that operates on pointers to X (X*).

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

Example:

 Q3PtrDict<char> fields; // void* keys, char* values

 QLineEdit *le1 = new QLineEdit( this );
 le1->setText( "Simpson" );
 QLineEdit *le2 = new QLineEdit( this );
 le2->setText( "Homer" );
 QLineEdit *le3 = new QLineEdit( this );
 le3->setText( "45" );

 fields.insert( le1, "Surname" );
 fields.insert( le2, "Forename" );
 fields.insert( le3, "Age" );

 Q3PtrDictIterator<char> it( fields );
 for( ; it.current(); ++it )
     cout << it.current() << endl;
 cout << endl;

 if ( fields[le1] ) // Prints "Surname: Simpson"
     cout << fields[le1] << ": " << le1->text() << endl;
 if ( fields[le2] ) // Prints "Forename: Homer"
     cout << fields[le2] << ": " << le2->text() << endl;

 fields.remove( le1 ); // Removes le1 from the dictionary
 cout << le1->text() << endl; // Prints "Simpson"

In this example we use a dictionary to add an extra property (a char*) to the line edits we're using.

See Q3Dict for full details, including the choice of dictionary size, and how deletions are handled.

See also Q3PtrDictIterator, Q3Dict, Q3AsciiDict, and Q3IntDict.

Member Function Documentation

 Q3PtrDict<ItemType> dict;
     ...
 if ( dict.find( key ) )
     dict.remove( key );
 dict.insert( key, item );