<reference id="GUID-F15B9BDF-EDF8-5684-A0FC-C0A08F9C1F22" xml:lang="en"><title>linkedlist: Using the Linked List classes</title><shortdesc/><prolog><metadata><keywords/></metadata></prolog><refbody>

<section id="GUID-4B81C04C-94DD-4694-9BD9-447ADE72B294"><p>The following

examples show the use of the linked list classes: </p> <ul>

<section id="GUID-4366D8F9-3E8F-53B2-BB3C-A32CA13DA96D"><title>Singly

linked list example</title> <p>This example application demonstrates

the use of singly linked lists. The templated <xref href="GUID-40BA1263-BE07-3C7F-955E-0BBC632E7C58.dita"><apiname>TSglQue</apiname></xref> class is used to create a singly linked list. </p> <p><b>Download</b> </p> <p>Click on the following link to download the example: <xref href="guid-6013a680-57f9-415b-8851-c4fa63356636/zips/guid-54304ba8-7028-43b8-89b8-d89432684981.zip" scope="external">sgllist.zip</xref></p><p>Click: <xref href="guid-6013a680-57f9-415b-8851-c4fa63356636/guid-54304ba8-7028-43b8-89b8-d89432684981.html" scope="peer">browse </xref>to view the example.</p> <p><b>Description</b> </p> <p>The example creates a singly linked list of objects of the <xref href="GUID-129B4F4D-500E-37E8-9D29-94E3E6D11BD9.dita"><apiname>TDigit</apiname></xref> class. This list represents a long number. An object

of class <xref href="GUID-F20187A8-CC62-34C6-830C-FB077515AAF8.dita"><apiname>CLongNumber</apiname></xref> owns the list. The user can

edit this list using the functions defined in the <codeph>CLongNumber</codeph> class. The following edit operations are possible: </p> <ul>

<li id="GUID-C793B73E-9037-5B22-8A3A-EFAD7A666D53"><p>Insert an object

of the <codeph>TDigit</codeph> class at the start of the singly linked

list </p> </li>

<li id="GUID-C46B31C9-49FF-5457-9157-E55316F26252"><p>Insert an object

of the <codeph>TDigit</codeph> class at the end of the singly linked

list </p> </li>

<li id="GUID-9AFD5005-AA6A-5D7D-9B96-35CBA4791128"><p>Remove an object

of the <codeph>TDigit</codeph> class from the end of the singly linked

list </p> </li>

</ul> <p>The user can perform any of these operations by pressing

keys specified in the menu. <codeph>CLongNumber</codeph> is an active

object class and handles the key press events in the <codeph>CLongNumber::RunL()</codeph> function.The <codeph>CLongNumber::ReadFunc()</codeph> function displays

a menu and waits for an asynchronous key press event. </p> <p>An object

of the templated <xref href="GUID-0A865633-5038-3320-A472-A2EE18F04FBE.dita"><apiname>TSglQueIter</apiname></xref> class is used to traverse

this linked list. The sum of all digits of the number represented

by the linked list is displayed to the user. </p> <p>An object of

the <xref href="GUID-D0AE0223-82DC-369A-A8FB-C2086C1EC77C.dita"><apiname>CAdder</apiname></xref> class is used to traverse the <codeph>CLongNumber::iNumber</codeph> list and print the sum of all digits

of the number represented by this list. The <codeph>CAdder::Add()</codeph> function gets this sum. </p><p><b>Related APIs</b></p><ul>

</ul> <p><b>Design and implementation</b> </p> <p>Figure 1 shows the

classes in the example. </p> <fig id="GUID-7BB458A7-C1E6-5919-A503-BFBE695432AA">

<title>     Figure 1. Classes in the singly linked list example  

            </title>

<image href="GUID-D6B332EB-D9D7-5598-98C7-E73164A2057D_d0e257464_href.jpg" placement="inline"/>

</ul><p><b>Build</b> </p> <p>For the emulator, the

example builds an executable called <filepath>sgllist.exe</filepath> in the <filepath>epoc32\release\winscw\&lt;udeb or urel&gt;\</filepath> folder. </p><p><b>See also:</b></p><p><xref href="GUID-052E9582-9A35-50B0-A32E-F7E6A01A2E2A.dita">Using Singly Linked

Lists</xref></p> </section>

<section id="GUID-FC5F8D9A-C594-5FBB-9AD1-8DEB72A5F5BD"><title>Doubly

linked list example</title> <p>This example application demonstrates

the use of doubly linked lists. The templated <xref href="GUID-E5E9834A-63CA-3F03-88D3-85B912ADA54C.dita"><apiname>TDblQue</apiname></xref> class is used create a doubly linked list. </p> <p><b>Download</b> </p> <p>Click on the following link to download the example: <xref href="guid-6013a680-57f9-415b-8851-c4fa63356636/zips/guid-3a268b1a-9a7e-49ae-bc76-f99bdc3b32f5.zip" scope="external">dbllist.zip</xref></p><p>Click: <xref href="guid-6013a680-57f9-415b-8851-c4fa63356636/guid-3a268b1a-9a7e-49ae-bc76-f99bdc3b32f5.html" scope="peer">browse </xref>to view the example code</p> <p><b>Description</b> </p> <p>The example creates a doubly linked list of objects of the <codeph>TLetter</codeph> class. This list represents a character string.

An object of class <codeph>CMyStringReverse</codeph> owns this string.

The user can edit this string using the functions defined in the <codeph>CMyStringReverse</codeph> class. The following edit operations are

possible: </p> <ul>

<li id="GUID-D3B39123-1249-59DD-BC1F-2D62B7F9DE84"><p>Insert a character

at the start of the list </p> </li>

<li id="GUID-E6CEC00A-B6C1-53B2-9AAA-870EA8B06A5B"><p>Insert a character

at the end of the list </p> </li>

</ul> <p>The user can perform either of these operations by pressing

keys specified in the menu. <codeph>CMyStringReverse</codeph> is an

active object class and handles key press events in the <codeph>CMyStringReverse::RunL()</codeph> function. The <codeph>CMyStringReverse::ReadFunc()</codeph> function

displays a menu and waits for an asynchronous key press event. </p> <p>The <codeph>CMyStringReverse</codeph> class has a doubly linked

list iterator, <codeph>iIteratorString</codeph>. The <codeph>iIteratorString</codeph> object iterates through the list <codeph>iString</codeph> from start

to end to print the string reversed. </p><p><b>Design and implementation</b></p><p>Figure 2 shows the classes in the example.</p><fig id="GUID-67F3F952-D0A8-4A28-8CB2-0394C1562A29">

<image href="GUID-21A1D1D2-524E-560E-88C8-16E2E49E2B7F_d0e257599_href.jpg" placement="inline"/>

<li><p><xref href="GUID-E5E9834A-63CA-3F03-88D3-85B912ADA54C.dita"><apiname>TDblQue</apiname></xref> - A templated class that provides

the behaviour for managing a doubly linked list.</p></li>

</ul> <p><b>Build</b> </p> <p>For the emulator, the example builds

an executable called <filepath>dbllist.exe</filepath> in the <filepath>epoc32\release\winscw\&lt;udeb or urel&gt;\</filepath> folder. </p> <p><b>See also</b> </p> <p><xref href="GUID-F45EA14E-F857-5D59-BFBA-E2F563287359.dita">Using Doubly Linked

Lists</xref>  </p> <p><b>Example code</b> </p> </section>

<section id="GUID-7FFDF885-72F4-543E-A93E-C6A57D3D7DE0"><title>Delta

queue example</title> <p>This example application demonstrates the

use of the delta queue. The templated <xref href="GUID-E67BB56F-F9DD-316D-BC16-ED60D31A5925.dita"><apiname>TDeltaQue</apiname></xref> class is used create a delta queue. </p> <p><b>Download</b> </p> <p>Click on the following link to download the example: <xref href="guid-6013a680-57f9-415b-8851-c4fa63356636/zips/guid-6a73c507-073b-4993-aa02-a677a384bafb.zip" scope="external">deltaque.zip</xref></p><p>Click: <xref href="guid-6013a680-57f9-415b-8851-c4fa63356636/guid-6a73c507-073b-4993-aa02-a677a384bafb.html" scope="peer">browse </xref>to view the example code.</p> <p><b>Description</b> </p> <p>The example creates an object of the <codeph>CTimerEntry</codeph> class. This is a <xref href="GUID-5733DF34-5B54-3044-BBED-3BFECB7ACE7A.dita"><apiname>CTimer</apiname></xref> derived class. An object

of this class generates timer events by using the <xref href="GUID-5733DF34-5B54-3044-BBED-3BFECB7ACE7A.dita#GUID-5733DF34-5B54-3044-BBED-3BFECB7ACE7A/GUID-F389C301-D56B-3981-9C26-180E02BFF171"><apiname>CTimer::After()</apiname></xref> function. The data member of this class, <codeph>iQueue</codeph> is a delta list. The offset value of each node in this list is the

tick count after each timer event. The <codeph>CTimerEntry::Arbitrator()</codeph> function decides the action to be performed for each event generated

by the timer. It either adds tick counts to the list or removes elements

from the list based on the state of the queue. </p><p><b>Related APIs</b></p><ul>

</ul><p><b>Design and implementation</b></p><p> Figure 3 shows the

classes of the example. </p><fig id="GUID-2E093EFA-7A18-4623-AE31-3FA1FDB103F5">

<image href="GUID-8CF0C00C-0FDF-517E-96FB-84F718237F61_d0e257722_href.jpg" placement="inline"/>

</ul> <p><b>Build</b> </p> <p>For the emulator, the example builds

an executable called <filepath>deltaque.exe</filepath> in the <filepath>epoc32\release\winscw\&lt;udeb or urel&gt;\</filepath> folder. </p> </section>