Array -keys

diff -r 48780e181b38 -r 578be2adaf3e Symbian3/PDK/Source/GUID-9309D482-8931-58FC-9B34-D0E5E942E404.dita --- a/Symbian3/PDK/Source/GUID-9309D482-8931-58FC-9B34-D0E5E942E404.dita Tue Jul 20 12:00:49 2010 +0100 +++ b/Symbian3/PDK/Source/GUID-9309D482-8931-58FC-9B34-D0E5E942E404.dita Fri Aug 13 16:47:46 2010 +0100 @@ -1,72 +1,72 @@ - - - - - -Array -keysThis document provides an introduction to array keys. -

A key is used by an array for sorting and finding elements and can also -be used to locate the insertion position for new elements.

The characteristics of a key are defined by a key object, constructed from -one of the three concrete classes: TKeyArrayFix, TKeyArrayVar and TKeyArrayPak. -In general, the choice of key class depends on the type of array being used -and the specific member function of that array.

TKeyArrayFix is used by the following functions accessible -through the CArrayFixFlat and CArrayFixSeg classes:

Sort()
InsertIsqL()
Find()
FindIsq()

TKeyArrayVar is used by the following functions accessible -through the CArrayVarFlat and CArrayVarSeg classes:

Sort()
InsertIsqL()
Find()
FindIsq()

TKeyArrayVar is also used by CArrayPakFlat::SortL().

TKeyArrayPak is used by the following functions accessible -through the CArrayPakFlat class:

InsertIsqL()
Find()
FindIsq()

The concrete classes are all derived from the abstract base class TKey that -encapsulates the characteristics of a key and defines the basic behaviour -of keys. A class such as TKeyArrayFix provides an implementation -for specific arrays or types of array.

A key object is not a component of an array class but is constructed separately -and passed, as an argument, to the appropriate array class member function. -A key definition is not an integral part of an array, but is used by -an array.

A TKey derived object is also passed as an argument to -the User::BinarySearch() and User::QuickSort() functions.

An array can use various different key definitions during its life.

The characteristics of a key as defined by the base TKey class -are:

The type of data forming -the key.
The type of comparison -to be made between two keys.
The length of the key -within an array element.
The location of the -key within an array element.