Concatination of 2 linked list objects of characters
Pleas help me to solve the following problem by using Java.
Problem: Write a program that concatenates two linked list objects of characters. The program should include method concatenate, which takes references to both list objects as arguments and concatenates the second list to the first list.
Thanking u,
Ripon
This assumes that your class is 'ListConcatenate' and that you have set up your two link-lists.
public void concatenate( ListConcatenate l1, ListConcatenate l2)
if ( l1.isEmpty1() || l2.isEmpty2() )
System.out.printf( "Empty %s or Empty %s\n", name1,name2 );
return;
System.out.printf( "%s concatenated with %s is: ", name1,name2 );
NodeOne current1 = l1.firstNode1;
NodeTwo current2 = l2.firstNode2;
while (current1 != null )
System.out.printf( "%s ", current1.data1.toString() + current2.data2.toString() );
current1 = current1.nextNode1;
current2 = current2.nextNode2;
}
Similar Messages
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Changing data in a linked list object.
hi,
i'm still pretty new to java, so bear with me if i am making stupid mistakes, heh.
i'm having trouble with changing data in an object stored in a singly-linked list. i've created a class that will store polynomials in sorted order (descending) in a singly-linked list. each linked list is one polynomial, and each node references to a polynomial object that stores two ints: the coefficient and the exponent of that term.
i'm having trouble when it comes to 'collecting like terms,' though. here's a rough skeleton of my code:
public class Polynomial
private LinkedList polynoList;
private LinkedListItr Itr;
private int coeff;
private int exponent;
public Polynomial()
zeroPolynomial();
} // this constructor sets up an empty linked list
public Polynomial( int c, int e )
coeff = c;
exponent = e;
} // this creates a Polynomial object storing the two ints
public void zeroPolynomial()
polynoList = new LinkedList();
theItr = polynoList.zeroth();
} // this method creates the empty linked list and sets the
//iterator on the zeroth node.
//various other methods are here, not relevant to my post
//this next method is the one i am having trouble with.
//it takes two ints as parameters, the coefficient
//and the exponent.
public void insertTerm( int c, int e )
//...i have a few if/then statements here
//so that the terms can be inserted in descending order.
LinkedListItr tester = polynoList.first();
//the 'tester' iterator is set on the first node
//this following if statement retrieves the exponent
//in the current node by casting the information
//retrieved from the LinkedList retrieve() method
//into Polynomial, then compares it to the current
//exponent. if they are equal, i want to add the
//coefficients.
if( e == ((Polynomial)tester.retrieve()).getExp() )
this.coeff = ((Polynomial)tester.retrieve()).getCoeff() + c;
//a main method goes here wherein the user can insert
//terms, print the polynomial, etc.
}//end Polynomial class
can anyone help me out? the code i'm using compiles correctly, but it does not change the value of the current coeff variable as i'd like to think it should. any input would be GREATLY appreciated, thanks!hey,
thanks for the reply...
i am sure that ((Polynomial)tester.retrieve()).getExp() will return an int equal to 'e.' i tried this:
System.out.println("e="+e);
System.out.println((Polynomial)tester.retrieve()).getExp());
if( e == ((Polynomial)tester.retrieve()).getExp() ){
this.coeff = ((Polynomial)tester.retrieve()).getCoeff() + c;
System.out.println( "this.coeff = " + this.coeff );
with that, the output showed that e and the getExp() output were the same. it also showed (as output) that this.coeff did change in value, but when i tried this:
System.out.println( ((Polynomial)tester.retrieve()).getCoeff() )
to check if the value changed within the object, it didn't. this.coeff changed, but the actual coeff variable in the object didn't.
any ideas? -
Help - can't print linked list object
Hi all,
I've written a program that creates an Airplane object. I've added the Airplane object to a linked list. I am trying to test by printing the linked list..but I get the addresses of the airplane object instead of the integer variables that the Airplane object contains. How can I fix this? Here's my output showing what I am talking about:
Airplane type: 2
Airplane arrival time: 600
Airplane cleaning time: 45
Airplane take-off time: 645
[Airplane@665753]
Airplane type: 3
Airplane arrival time: 1100
Airplane cleaning time: 60
Airplane take-off time: 1160
[Airplane@665753, Airplane@ef22f8]
Airplane type: 1
Airplane arrival time: 900
Airplane cleaning time: 30
Airplane take-off time: 930
[Airplane@665753, Airplane@ef22f8, Airplane@e0cf70]
Airplane type: 1
Airplane arrival time: 1100
Airplane cleaning time: 30
Airplane take-off time: 1130
[Airplane@665753, Airplane@ef22f8, Airplane@e0cf70, Airplane@52fe85]
Airplane type: 3
Airplane arrival time: 1000
Airplane cleaning time: 60
Airplane take-off time: 1060
[Airplane@665753, Airplane@ef22f8, Airplane@e0cf70, Airplane@52fe85, Airplane@c40c80]
Airplane type: 2
Airplane arrival time: 900
Airplane cleaning time: 45
Airplane take-off time: 945
[Airplane@665753, Airplane@ef22f8, Airplane@e0cf70, Airplane@52fe85, Airplane@c40c80, Airplane@10d81b]
Airplane type: 2
Airplane arrival time: 900
Airplane cleaning time: 45
Airplane take-off time: 945
[Airplane@665753, Airplane@ef22f8, Airplane@e0cf70, Airplane@52fe85, Airplane@c40c80, Airplane@10d81b, Airplane@dbe178]
Airplane type: 3
Airplane arrival time: 1000
Airplane cleaning time: 60
Airplane take-off time: 1060
[Airplane@665753, Airplane@ef22f8, Airplane@e0cf70, Airplane@52fe85, Airplane@c40c80, Airplane@10d81b, Airplane@dbe178, Airplane@af9e22]
Airplane type: 1
Airplane arrival time: 900
Airplane cleaning time: 30
Airplane take-off time: 930
[Airplane@665753, Airplane@ef22f8, Airplane@e0cf70, Airplane@52fe85, Airplane@c40c80, Airplane@10d81b, Airplane@dbe178, Airplane@af9e22, Airplane@b6ece5]
Airplane type: 1
Airplane arrival time: 700
Airplane cleaning time: 30
Airplane take-off time: 730
[Airplane@665753, Airplane@ef22f8, Airplane@e0cf70, Airplane@52fe85, Airplane@c40c80, Airplane@10d81b, Airplane@dbe178, Airplane@af9e22, Airplane@b6ece5, Airplane@7ace8d]
Airplane@665753
import java.io.*;
import java.util.*;
public class AirPortSimulator {
public static void main(String[] args) {
LinkedList<Airplane> myEventList = new LinkedList();
//for loop to test random number generator for airplane type
for( int i = 0; i < 10; i++){
int parOne = myNumber();
System.out.println("Airplane type: " + parOne);
int parTwo = myTime();
System.out.println("Airplane arrival time: " + parTwo);
int parThree = 0;
switch(parOne){
case 1: parThree = 30;break;
case 2: parThree = 45;break;
case 3: parThree = 60;break;
System.out.println("Airplane cleaning time: " + parThree);
int parFour=0;
switch(parOne){
case 1: parFour = parTwo + 30;break;
case 2: parFour = parTwo + 45;break;
case 3: parFour = parTwo + 60;break;
System.out.println("Airplane take-off time: " + parFour);
System.out.println();
Airplane myAirplane = new Airplane(parOne, parTwo, parThree, parFour);
myEventList.addLast(myAirplane);
System.out.println(myEventList);
System.out.println();
public static int myTime(){
Random generator = new Random();
int number = generator.nextInt(16)+1;
number = number * 100;
if (number < 600){
number = number + 600;
return number;
public static int myNumber(){
Random generator = new Random();
return generator.nextInt(3)+1;
}I've written a method before that prints all the
elements of a linked list..but that method onlyheld
one integer or string...it was a "while (head !=
null) loop that traversed the list and printed
"head.info"
But i'm confused with an object that has 4integers
inside it...You don't have to write any kind of loop. The
LinkedList implementation of toString does that for
you. All you have to do is write a toString for
Airplane that prints whatever you feel is important
for a single Airplane object.
But note that since the list uses commas to separate
entries, your toString method will be clearer if you
can write it in such a way that it doesn't use
commas, or so that you can see where the output
begins and ends. For example, maybe you can wrap the
output with curly brackets.Thanks, I just had to understand what the toString method was and then how to override it. This works well:
Thank you for pointing me in the right direction.
aiki985
public String toString(){
return "{" + airplaneType + ", " + arrivalTime + ", " +
waitingTime + ", " + departureTime + "}";
} // end toString method -
Inserting integers in a Linked list/List in Java
Please solve the following problem using Java.
Problem: Write a program that inserts 25 random integers from 0 to 100 in order in a linked list object. The program should calculate the sum of the elements and the floating-point average of the elements.
Thanks
Ripondo the following 25 times
. insert random value between x and y into my list
All you have to do is replace x and y with your values and compile using the java -idiot option. -
Using Collections.binarySearch on a Linked list
hi all
i want to use the Collections.binarySearch method on a linked list object to add items to it. These items are of type Entry (a class i have created).
i have the following code:
public void addEntry(Entry newEntry)
int pos = Collections.binarySearch(entryList, newEntry);
if (pos < 0)
entryList.add(-(pos) -1, newEntry);
[\CODE]
where entryList is declared as:
private List entryList = new LinkedList();
This code compiles OK, but when i run it to add an Entry element to the linked list, i get a ClassCastException being thrown, and im not sure why.
i can add one Entry object to the list ok, but it falls over when i try to add another. im trying to order my Entry objects by a field called 'surname', so the binarySearch finds the correct location in the list for the new entry and then it is added.
any help on this would be appreciated
cheers
davidbinarySearch doesn't work on a linked listSo untrue:Well, only mostly untrue. It still doesn't really do a binary search on your linked list
From the javadoc
'This method runs in log(n) time for a "random access" list (which provides near-constant-time positional access). If the specified list does not implement the RandomAccess and is large, this method will do an iterator-based binary search that performs O(n) link traversals and O(log n) element comparisons. '
import java.util.*;
public class Test {
public static void main(String[] args) {
List entryList = new LinkedList();
entryList.add(new Integer(3));
entryList.add(new Integer(5));
entryList.add(new Integer(1));
Collections.sort(entryList);
System.out.println(Collections.binarySearch(entryList,
new Integer(5)));
}Compiles and runs without any problems -
Hi there,
i have just started to use java and was on the topic of doubly linked list and am confused. Is it possible for someone to show me how to implement a doubly linked list????
Thanxif i had to do it, then i'd make a class that's this linked list object, and another class that's node object.
in list object i'd hold count of nodes (in case someone asks that, so i should not go through list and count all those 1000000 nodes), and would also have reference to first and last node.
public class KstyleDLList {
KstyleNode first = null;
KstyleNode last = null;
private int count;
public int getCount() {
return count;
public void addNode(KstyleNode node) {
last.setNext(node); // simply ignore returned value
// because if everything is OK, then value returned is null
next = node;
public void removeNode(int index) {
// method body here
public KstyleNode getFirst() {
// method body here
public Kstyle getLast() {
// method body here
class KstyleNode {
private KstyleNode next = null;
private KstyleNode prev = null;
public KstyleNode setNext(KstyleNode next) {
KstyleNode old = this.next;
this.next = next;
return old;
public getNext() {
// method body here
public KstyleNode setPrev(KstyleNode prev) {
// method body here
public KstyleNode getPrev() {
// method body here
}and lots of other methods that i haven't implemented yet.. but this should give you some idea of what you're going to do... -
How to use methods when objects stored in a linked list?
Hi friend:
I stored a series of objects of certain class inside a linked list. When I get one of them out of the list, I want to use the instance method associated with this object. However, the complier only allow me to treat this object as general object, ( of Object Class), as a result I can't use instance methods which are associated with this object. Can someone tell me how to use the methods associated with the objects which are stored inside a linked list?
Here is my code:
import java.util.*;
public class QueueW
LinkedList qList;
public QueueW(Collection s) //Constructor of QuequW Class
qList = new LinkedList(s); //Declare an object linked list
public void addWaiting(WaitingList w)
boolean result = qList.isEmpty(); //true if list contains no elements
if (result)
qList.addFirst(w);
else
qList.add(w);
public int printCid()
Object d = qList.getFirst(); // the complier doesn't allow me to treat d as a object of waitingList class
int n = d.getCid(); // so I use "Object d"
return n; // yet object can't use getCid() method, so I got error in "int n = d.getCid()"
public void removeWaiting(WaitingList w)
qList.removeFirst();
class WaitingList
int cusmNo;
String cusmName;
int cid;
private static int id_count = 0;
/* constructor */
public WaitingList(int c, String cN)
cusmNo = c;
cusmName = cN;
cid = ++id_count;
public int getCid() //this is the method I want to use
return cid;Use casting. In other words, cat the object taken from the collection to the correct type and call your method.
HashMap map = /* ... */;
map.put(someKey, myObject);
((MyClass)(map.get(someKey)).myMethod();Chuck -
Putting a class of objects in a Linked List?
Hi,
I copied a program from a book and I want to edit it and put studentRecord class in the Linked List. I've tried to play about with datum, but everything I try doesn't work. Can someone help me out? How could I put studentRecord in the LinkedList?
import java.io.*;
class IO
static BufferedReader keyboard = new
BufferedReader(new InputStreamReader(System.in));
static PrintWriter screen = new PrintWriter(System.out, true);
class studentRecord
private String name;
private int IDNumber;
class LinkedList
class Node
protected Object datum;
protected Node link;
public Node() {}
public Node(Object item, Node pointer)
datum = item;
link = pointer;
private Node head;
private Node tail;
private Node temporary;
private int nodeCount = 0;
//constructor
public LinkedList()
head = null;
tail = null;
temporary = null;
//method to insert an object into the linked list
public void insert(Object datum)
if (head == null) // list empty
head = new Node(datum, head);
tail = head;
else
temporary = new Node(datum, temporary);
tail.link = temporary;
tail = temporary;
temporary = null;
nodeCount++;
Full program can be found: http://dil3mma.tripod.com/LinkedList.txt
Thanks in advance.Hi jverd,
Thanks for replying. I've tried to change the program liked you said but there is 1 error I can't seem to fix(Im sure there are more tho). The error is "cannot resolve symbol" I typed in caps the line it happens on so it's easy to see. Any idea what it could be? Is it cause I'm comparing a String with Object?
import java.io.*;
class IO
static BufferedReader keyboard = new
BufferedReader(new InputStreamReader(System.in));
static PrintWriter screen = new PrintWriter(System.out, true);
class sRecord
private String name;
private int IDNumber;
class LinkedList
class Node
protected sRecord datum;
protected Node link;
public Node() {}
public Node(sRecord item, Node pointer)
datum = item;
link = pointer;
private Node head;
private Node tail;
private Node temporary;
private int nodeCount = 0;
//constructor
public LinkedList()
head = null;
tail = null;
temporary = null;
//method to insert an object into the linked list
public void insert(sRecord datum)
if (head == null) // list empty
head = new Node(datum, head);
tail = head;
else
temporary = new Node(datum, temporary);
tail.link = temporary;
tail = temporary;
temporary = null;
nodeCount++;
//method to delete an object from the linked list
public boolean delete(Object scrap)
Node previous = head;
//for every node in the linked list
for (Node current = head; current != null; current = current.link)
//node to be deleted is at the head of the list
if (current.datum.equals(scrap) && previous == current)
head = current.link;
if (head == null) tail = null;
nodeCount--;
return true;
//node to be deleted is after the first node and before the last
else if (current.datum.equals(scrap) && (current.link != null))
previous.link = current.link;
nodeCount--;
return true;
//node to be deleted is at the ned of list
else if (current.datum.equals(scrap) && (current.link == null))
tail = previous;
previous.link = null;
nodeCount--;
return true;
previous = current;
return false;
//method to display the contents of a linked list
public void displayList()
Node temporary = head;
if (head == null)
IO.screen.println("linked list is empty");
return;
while (temporary != null)
IO.screen.println(temporary.datum);
temporary = temporary.link;
//method to return true if the linked list is empty
public boolean isEmpty()
return (nodeCount == 0);
//method to return the number of nodes in the linked list
public int nodes()
return nodeCount;
//method to display a menu to insert data into the linked list
static private char menu()
char response = '\u0000';
IO.screen.println("Do you want to ");
IO.screen.print("nsert, [D]elete, [L]ist, [E]xit? ");
IO.screen.flush();
boolean done=false;
do
try
String data = IO.keyboard.readLine();
response = Character.toUpperCase(data.charAt(0));
done = true;
catch (Exception e)
IO.screen.println("Please input a single character I, D, L or E");
} while (! done);
return response;
static public void main(String[] args) throws IOException
LinkedList list = new LinkedList();
String datum;
char choice;
//get information from menu
choice = menu();
for (;;)
//Menu
switch (choice)
case 'I' :
IO.screen.println("type quit to finish input");
IO.screen.print("Enter a word ");
IO.screen.flush();
datum = IO.keyboard.readLine();
while (! datum.equals("quit"))
THE ERROR HAPPENS HERE ON THIS LINE list.insert(datum.name);
IO.screen.print("Enter another word");
IO.screen.flush();
datum = IO.keyboard.readLine();
break;
case 'D' :
//if list is empty deletion not possible
if (list.isEmpty())
IO.screen.println("linked list is empty");
break;
IO.screen.println("type quit to finish input");
IO.screen.print("Delete? ");
IO.screen.flush();
datum = IO.keyboard.readLine();
while (! datum.equals("quit"))
if (list.delete(datum))
IO.screen.println(datum+" was scrapped!");
//if list is empty deletion is not possible
if (list.isEmpty())
IO.screen.println("linked list is empty");
break;
IO.screen.print("Delete? ");
IO.screen.flush();
datum = IO.keyboard.readLine();
break;
case 'L' :
list.displayList();
IO.screen.println("number of nodes " + list.nodes());
break;
case 'E' : System.exit(0);
//get information from menu
choice = menu(); -
Hi am trying to create a linked list out of an object i have called ClassID.
I have a Link class (that creates a node correct?):
import java.io.*;
public class Link
public ClassID id;
public Link next;
public Link(ClassID inID)
this(inID, null);
public Link(ClassID inID, Link next)
id = inID;
next = next;;
public void displayLink() // display ourself
id.toString();
} // end class LinkIf it does create node then I have a class called LinkList with the following insert method:
private Link first; // ref to first link on list
// insert at start of list
public void insertFirst(Link id)
{ // make new link
Link newLink = new Link(id);
newLink.next = first; // newLink --> old first
first = newLink; // first --> newLinkBut it doesnt seem to be working, could someone help me.
Thanks
Phil
Edited by: The_One on Sep 13, 2008 1:49 AMI dont think its doing it properly. Iv tried goign through it but cant find the problem. Might be a problem with displaylist
Let me paste all my classes:
LINK METHOD:
import java.io.*;
public class Link
public ClassID id;
public Link next;
public Link(ClassID inID)
this(inID, null);
public Link(ClassID inID, Link next)
id = inID;
next = next;;
public void displayLink() // display ourself
id.toString();
} // end class LinkLINKLIST METHOD:
class LinkList
private Link first; // ref to first link on list
public LinkList() // constructor
first = new Link(null); // no items on list yet
public boolean isEmpty() // true if list is empty
return (first==null);
// insert at start of list
public void insertFirst(ClassID id)
{ // make new link
Link newLink = new Link(id);
newLink.next = first; // newLink --> old first
first = newLink; // first --> newLink
public void displayList()
System.out.print("List (first-->last): ");
Link current = first; // start at beginning of list
while(current != null) // until end of list,
current.displayLink(); // print data
current = current.next; // move to next link
System.out.println("");
................. SOME MORE METHODS..........MAIN METHOD:
import java.io.*;
public class SortListApp
public static void main(String[] args)
BufferedReader inputStream = null;
LinkList list = new LinkList();
try
inputStream = new BufferedReader(new FileReader("data.txt"));
String inName;
int inIDNum;
int inACNum;
long inTime;
int inTransmode;
//while ((inName = (inputStream.readLine()) ) != null)
inName = inputStream.readLine();
inIDNum = Integer.parseInt(inputStream.readLine());
inACNum = Integer.parseInt(inputStream.readLine());
inTime = Long.parseLong(inputStream.readLine());
inTransmode = Integer.parseInt(inputStream.readLine());
list.insertFirst(new ClassID(inName, inIDNum, inACNum, inTime, inTransmode));
list.displayList();
//System.out.println("Printed to file");
//list.sort();
inputStream.close();
catch (IOException error)
System.out.println("Error in file");
}Edited by: The_One on Sep 13, 2008 2:41 AM -
Revision: 18926
Revision: 18926
Author: [email protected]
Date: 2010-12-01 14:07:19 -0800 (Wed, 01 Dec 2010)
Log Message:
bug fix BLZ-570 Double linked list with lot of objects result in BlazeDS Error deserializing error : StackOverflowError
We put hard limit to the max object nest level to prevent StackOverFlowError. the default max object nest level is 1024 and it can be configured in the endpoint/serialziation section in service-config.xml.
This needs documentation.
Checkintests pass
Ticket Links:
http://bugs.adobe.com/jira/browse/BLZ-570
Modified Paths:
blazeds/trunk/modules/common/src/flex/messaging/errors.properties
blazeds/trunk/modules/core/src/flex/messaging/endpoints/AbstractEndpoint.java
blazeds/trunk/modules/core/src/flex/messaging/io/SerializationContext.java
blazeds/trunk/modules/core/src/flex/messaging/io/amf/Amf0Input.java
blazeds/trunk/modules/core/src/flex/messaging/io/amf/Amf3Input.java
blazeds/trunk/modules/core/src/flex/messaging/io/amf/AmfIO.java -
Revision: 20451
Revision: 20451
Author: [email protected]
Date: 2011-02-24 08:33:31 -0800 (Thu, 24 Feb 2011)
Log Message:
backporting bug fix BLZ-570/BLZ-620 Double linked list with lot of objects result in BlazeDS Error deserializing error : StackOverflowError We put hard limit to the max object nest level to prevent StackOverFlowError. the default max object nest level is 1024 and it can be configured in the endpoint/serialziation section in service-config.xml. This needs documentation. Checkintests pass
Ticket Links:
http://bugs.adobe.com/jira/browse/BLZ-570
http://bugs.adobe.com/jira/browse/BLZ-620
Modified Paths:
blazeds/branches/4.0.0_fixes/modules/common/src/flex/messaging/errors.properties
blazeds/branches/4.0.0_fixes/modules/core/src/flex/messaging/endpoints/AbstractEndpoint.j ava
blazeds/branches/4.0.0_fixes/modules/core/src/flex/messaging/io/SerializationContext.java
blazeds/branches/4.0.0_fixes/modules/core/src/flex/messaging/io/amf/Amf0Input.java
blazeds/branches/4.0.0_fixes/modules/core/src/flex/messaging/io/amf/Amf3Input.java
blazeds/branches/4.0.0_fixes/modules/core/src/flex/messaging/io/amf/AmfIO.javaDear Pallavi,
Very useful post!
I am looking for similar accelerators for
Software Inventory Accelerator
Hardware Inventory Accelerator
Interfaces Inventory
Customization Assessment Accelerator
Sizing Tool
Which helps us to come up with the relevant Bill of Matetials for every area mentioned above, and the ones which I dont know...
Request help on such accelerators... Any clues?
Any reply, help is highly appreciated.
Regards
Manish Madhav -
Revision: 20443
Revision: 20443
Author: [email protected]
Date: 2011-02-23 21:19:22 -0800 (Wed, 23 Feb 2011)
Log Message:
back porting bug fix BLZ-570/BLZ-620 Double linked list with lot of objects result in BlazeDS Error deserializing error : StackOverflowError We put hard limit to the max object nest level to prevent StackOverFlowError. the default max object nest level is 1024 and it can be configured in the endpoint/serialziation section in service-config.xml. This needs documentation. Checkintests pass
Ticket Links:
http://bugs.adobe.com/jira/browse/BLZ-570
http://bugs.adobe.com/jira/browse/BLZ-620
Modified Paths:
blazeds/branches/3.x/modules/common/src/java/flex/messaging/errors.properties
blazeds/branches/3.x/modules/core/src/java/flex/messaging/endpoints/AbstractEndpoint.java
blazeds/branches/3.x/modules/core/src/java/flex/messaging/io/SerializationContext.java
blazeds/branches/3.x/modules/core/src/java/flex/messaging/io/amf/Amf0Input.java
blazeds/branches/3.x/modules/core/src/java/flex/messaging/io/amf/Amf3Input.java
blazeds/branches/3.x/modules/core/src/java/flex/messaging/io/amf/AmfIO.java -
Hello everyone. Just working on a little program but have got a little stuck
So here's one of my classes:
import java.util.LinkedList;
import java.util.ListIterator;
import java.io.*;
* A program that demonstrates the LinkedList class
public class BookList
LinkedList<String> books = new LinkedList<String>();
ListIterator<String> iterator = books.listIterator();
public BookList()
public void DisplayBooks()
iterator = books.listIterator();
while (iterator.hasNext())
System.out.println(iterator.next());
public void AddBook(String author, String title){
Book newBook = new Book(author, title);
books.addFirst(newBook);
}I want to be able to add a new book object to my linked list but it want compile. Any help would be very appreciated. Thanks in advanced.As books is a list of String it can't accept a Book object !
LinkedList<Book> books = new LinkedList<Book>(); -
Linked List, Stacks and Other Data Structures in Objective-C 2.0
I've checked a little throughout documentation that Apple provides for the different frameworks in order to determine if there were ready-made classes for data structures such as linked lists, stacks and so forth but there don't appear to be any available? Is this correct?
NSArray and NSDictionary are the multi-purpose built-in aggregate types. If you need something else then you can use STL or roll your own.
-
Need help regarding Linked List
I'm a beginner who just spent ages working on the following code.. but need help on re-implementing the following using a linked list, i.e. no array is allowed for customer records but you still can use arrays for names, address, etc.. Hopefully I've inserted enough comments..
Help very much appreciated!! Thanks! =]
import java.util.Scanner;
import java.io.*;
public class Bank
/* Private variables declared so that the data is only accessible to its own
class, but not to any other class, thus preventing other classes from
referring to the data directly */
private static Customer[] customerList = new Customer[30];
//Array of 30 objects created for storing information of each customer
private static int noOfCustomers;
//Integer used to store number of customers in customerList
public static void main(String[] args)
Scanner sc = new Scanner(System.in);
menu();
public static void menu()
char choice;
String filename;
int custId,counter=0;
double interestRate;
Scanner sc = new Scanner(System.in);
do
//Displaying of Program Menu for user to choose
System.out.println("ABC Bank Customer Management System Menu");
System.out.println("========================================");
System.out.println("(1) Input Data from File");
System.out.println("(2) Display Data");
System.out.println("(3) Output Data to File");
System.out.println("(4) Delete Record");
System.out.println("(5) Update Record");
System.out.println("(Q) Quit");
System.out.println();
System.out.print("Enter your choice: ");
String input = sc.next();
System.out.println();
choice = input.charAt(0);
//switch statement used to assign each 'selection' to its 'operation'
switch(choice)
case '1': int noOfRecords;
System.out.print("Enter file name: ");
sc.nextLine();
filename = sc.nextLine();
System.out.println();
noOfRecords = readFile(filename);
System.out.println(+noOfRecords+" records read.");
break;
case '2': displayRecords();
break;
case '3': writeFile();
break;
case '4': System.out.print("Enter account ID to be deleted: ");
sc.nextLine();
custId = sc.nextInt();
deleteRecord(custId);
break;
case '5': if(counter==0)
System.out.print("Enter current interest rate for saving account: ");
sc.nextLine();
interestRate = sc.nextDouble();
update(interestRate);
counter++;
else
System.out.println("Error: Accounts have been updated for the month.");
break;
}System.out.println();
}while(choice!='Q' && choice!='q');
/* The method readFile() loads the customer list of a Bank from a specified
text file fileName into customerList to be stored as array of Customer
objects in customerList in ascending alphabetical order according to the
customer names */
public static int readFile(String fileName)
int custId,i=0;
String custName,custAddress,custBirthdate,custPhone,custAccType;
double custBalance,curRate;
boolean d;
/* Try block to enclose statements that might throw an exception, followed by
the catch block to handle the exception */
try
Scanner sc = new Scanner(new File(fileName));
while(sc.hasNext())
/* sc.next() gets rid of "Account", "Id" and "=" */
sc.next();sc.next();sc.next();
custId = sc.nextInt();
d=checkDuplicate(custId);
/* checkDuplicate() is a method created to locate duplicating ids in array */
if(d==true)
/* A return value of true indicates duplicating record and the sc.nextLine()
will get rid of all the following lines to read the next customer's record */
sc.nextLine();sc.nextLine();sc.nextLine();
sc.nextLine();sc.nextLine();sc.nextLine();
continue;
/* A return value of false indicates no duplicating record and the following
lines containing the information of that customer's record is being read
in */
if(d==false)
/* sc.next() gets rid of "Name" and "=" and name is changed to upper case*/
sc.next();sc.next();
custName = sc.nextLine().toUpperCase();
/* sc.nextLine get rids of the following lines to read the next customer's
record if length of name is more than 20 characters*/
if(custName.length()>21)
System.out.println("Name of custId "+custId+" is more than 20 characters");
System.out.println();
sc.nextLine();sc.nextLine();sc.nextLine();sc.nextLine();
continue;
/* sc.next() gets rid of "Address" and "=" */
sc.next();sc.next();
custAddress = sc.nextLine();
/* sc.nextLine get rids of the following lines to read the next customer's
record if length of address is more than 80 characters*/
if(custAddress.length()>81)
System.out.println("Address of custId "+custId+" is more than 80 characters");
System.out.println();
sc.nextLine();sc.nextLine();sc.nextLine();sc.nextLine();
continue;
/* sc.next() gets rid of "DOB" and "=" */
sc.next();sc.next();
custBirthdate = sc.nextLine();
/* sc.nextLine get rids of the following lines to read the next customer's
record if length of date of birth is more than 10 characters*/
if(custBirthdate.length()>11)
System.out.println("D.O.B of custId "+custId+" is more than 10 characters");
System.out.println();
sc.nextLine();sc.nextLine();sc.nextLine();sc.nextLine();
continue;
/* sc.next() gets rid of "Phone", "Number" and "=" */
sc.next();sc.next();sc.next();
custPhone = sc.nextLine();
/* sc.nextLine get rids of the following lines to read the next customer's
record if length of phone number is more than 8 characters*/
if(custPhone.length()>9)
System.out.println("Phone no. of custId "+custId+" is more than 8 characters");
System.out.println();
sc.nextLine();sc.nextLine();sc.nextLine();sc.nextLine();
continue;
/* sc.next() gets rid of "Account", "Balance" and "=" */
sc.next();sc.next();sc.next();
custBalance = sc.nextDouble();
/* sc.next() gets rid of "Account", "Type" and "=" */
sc.next();sc.next();sc.next();
custAccType = sc.next();
if(custAccType.equals("Saving"))
customerList[noOfCustomers] = new Account1(custId,custName,custAddress,custBirthdate,custPhone,custBalance,custAccType);
sc.nextLine();
noOfCustomers++;
i++;
else if(custAccType.equals("Checking"))
customerList[noOfCustomers] = new Account2(custId,custName,custAddress,custBirthdate,custPhone,custBalance,custAccType);
sc.nextLine();
noOfCustomers++;
i++;
else if(custAccType.equals("Fixed"))
sc.next();sc.next();sc.next();sc.next();
curRate = sc.nextDouble();
Account3 temp = new Account3(custId,custName,custAddress,custBirthdate,custPhone,custBalance,custAccType,curRate);
customerList[noOfCustomers]=temp;
sc.nextLine();
noOfCustomers++;
i++;
else
System.out.println("Account type not defined.");
if(noOfCustomers==30)
System.out.println("The customer list has reached its maximum limit of 30 records!");
System.out.println();
return noOfCustomers;
//Exceptions to be caught
catch (FileNotFoundException e)
System.out.println("Error opening file");
System.exit(0);
catch (IOException e)
System.out.println("IO error!");
System.exit(0);
/* Bubblesort method used to sort the array in ascending alphabetical order
according to customer's name */
bubbleSort(customerList);
return i;
/* The method displayRecords() displays the data of the customer records on
screen */
public static void displayRecords()
int k;
/* Displaying text using the printf() method */
for(k=0;k<noOfCustomers;k++)
System.out.printf("Name = %s\n", customerList[k].getName());
System.out.printf("Account Balance = %.2f\n", customerList[k].getBalance());
System.out.printf("Account Id = %d\n", customerList[k].getId());
System.out.printf("Address = %s\n", customerList[k].getAddress());
System.out.printf("DOB = %s\n", customerList[k].getBirthdate());
System.out.printf("Phone Number = %s\n", customerList[k].getPhone());
String type = customerList[k].getAccType();
System.out.println("Account Type = " +type);
if(type.equals("Fixed"))
System.out.println("Fixed daily interest = "+((Account3)customerList[k]).getFixed());
System.out.println();
/* The method writeFile() saves the content from customerList into a
specified text file. Data is printed on the screen at the same time */
public static void writeFile()
/* Try block to enclose statements that might throw an exception, followed by
the catch block to handle the exception */
try
int i;
int n=0;
//PrintWriter class used to write contents of studentList to specified file
FileWriter fwStream = new FileWriter("newCustomers.txt");
BufferedWriter bwStream = new BufferedWriter(fwStream);
PrintWriter pwStream = new PrintWriter(bwStream);
for(i=0;i<noOfCustomers;i++)
pwStream.println("Account Id = "+customerList.getId());
pwStream.println("Name = "+customerList[i].getName());
pwStream.println("Address = "+customerList[i].getAddress());
pwStream.println("DOB = "+customerList[i].getBirthdate());
pwStream.println("Phone Number = "+customerList[i].getPhone());
pwStream.printf("Account Balance = %.2f\n", customerList[i].getBalance());
pwStream.println("Account Type = "+customerList[i].getAccType());
if(customerList[i].getAccType().equals("Fixed"))
pwStream.println("Fixed Daily Interest = "+((Account3)customerList[i]).getFixed());
pwStream.println();
n++;
//Closure of stream
pwStream.close();
System.out.println(+n+" records written.");
catch(IOException e)
System.out.println("IO error!");
System.exit(0);
//Deletes specified record from list
public static void deleteRecord(int id)
int i;
i=locate(id);
if(i==200)
//checking if account to be deleted does not exist
System.out.println("Error: no account with the id of "+id+" found!");
//if account exists
else
while(i<noOfCustomers)
customerList[i] = customerList[i+1];
i++;
System.out.println("Account Id: "+id+" has been deleted");
--noOfCustomers;
//Updates the accounts
public static void update(double interest)
int i,j,k;
double custBalance,addition=0;
for(i=0;i<noOfCustomers;i++)
if(customerList[i] instanceof Account1)
for(j=0;j<30;j++)
addition=customerList[i].getBalance()*interest;
custBalance=customerList[i].getBalance()+addition;
customerList[i].setBalance(custBalance);
else if(customerList[i] instanceof Account2)
continue;
else if(customerList[i] instanceof Account3)
for(j=0;j<30;j++)
addition=customerList[i].getBalance()*((Account3)customerList[i]).getFixed();
custBalance=customerList[i].getBalance()+addition;
customerList[i].setBalance(custBalance);
else
System.out.println("Account type not defined");
System.out.println("The updated balances are: \n");
for(k=0;k<noOfCustomers;k++)
System.out.printf("Name = %s\n", customerList[k].getName());
System.out.printf("Account Balance = %.2f\n", customerList[k].getBalance());
System.out.println();
/* ================== Additional methods ==================== */
/* Bubblesort method to sort the customerList in ascending alphabetical
order according to customer's name */
public static void bubbleSort(Customer[] x)
int pass, index;
Customer tempValue;
for(pass=0; pass<noOfCustomers-1; pass++)
for(index=0; index<noOfCustomers-1; index++)
if(customerList[index].getName().compareToIgnoreCase(customerList[index+1].getName()) > 0)
tempValue = x[index];
x[index] = x[index+1];
x[index+1]= tempValue;
/* Method used to check for duplicated ids in array */
public static boolean checkDuplicate(int id)
int i;
for(i=0;i<noOfCustomers;i++)
if(id == customerList[i].getId())
System.out.println("Account Id = "+id+" already exists");
System.out.println();
return true;
}return false;
/* Method to seach for account id in array */
public static int locate(int id)
int j;
for(j=0;j<noOfCustomers;j++)
if(customerList[j].getId()==id)
return j;
j=200;
return j;
import java.util.Scanner;
public class Customer
/* The following private variables are declared so that the data is only
accessible to its own class,but not to any other class, thus preventing
other classes from referring to the data directly */
protected int id;
protected String name,address,birthdate,phone,accType;
protected double balance;
// Null constructor of Customer
public Customer()
id = 0;
name = null;
address = null;
birthdate = null;
phone = null;
balance = 0;
accType = null;
/* The following statements with the keyword this activates the Customer
(int id, String name String address, String birthdate, String phone, double
balance) constructor that has six parameters of account id, name, address,
date of birth, phone number, account balance and assign the values of the
parameters to the instance variables of the object */
public Customer(int id, String name, String address, String birthdate, String phone, double balance, String accType)
//this is the object reference that stores the receiver object
this.id = id;
this.name = name;
this.address = address;
this.birthdate = birthdate;
this.phone = phone;
this.balance = balance;
this.accType = accType;
/* The following get methods getId(), getName(), getAddress(), getBirthdate(),
getPhone(), getBalance() return the values of the corresponding instance
properties */
public int getId()
return id;
public String getName()
return name;
public String getAddress()
return address;
public String getBirthdate()
return birthdate;
public String getPhone()
return phone;
public double getBalance()
return balance;
public String getAccType()
return accType;
/* The following set methods setId(), setName(), setAddress(), setBirthdate(),
setPhone and setBalance() set the values of the corresponding instance
properties */
public void setId (int custId)
id = custId;
public void setName(String custName)
name = custName;
public void setAddress (String custAddress)
address = custAddress;
public void setBirthdate (String custBirthdate)
birthdate = custBirthdate;
public void setPhone (String custPhone)
phone = custPhone;
public void setBalance (double custBalance)
balance = custBalance;
public void setAccType (String custAccType)
accType = custAccType;
class Account1 extends Customer
public Account1(int id, String name, String address, String birthdate, String phone, double balance, String accType)
super(id,name,address,birthdate,phone,balance,accType);
this.id = id;
this.name = name;
this.address = address;
this.birthdate = birthdate;
this.phone = phone;
this.balance = balance;
this.accType = accType;
class Account2 extends Customer
public Account2(int id, String name, String address, String birthdate, String phone, double balance, String accType)
super(id,name,address,birthdate,phone,balance,accType);
this.id = id;
this.name = name;
this.address = address;
this.birthdate = birthdate;
this.phone = phone;
this.balance = balance;
this.accType = accType;
class Account3 extends Customer
protected double fixed=0;
public Account3(int id, String name, String address, String birthdate, String phone, double balance, String accType, double fixed)
super(id,name,address,birthdate,phone,balance,accType);
this.id = id;
this.name = name;
this.address = address;
this.birthdate = birthdate;
this.phone = phone;
this.balance = balance;
this.accType = accType;
this.fixed = fixed;
public double getFixed()
return fixed;
Example of a customers.txt
Account Id = 123
Name = Matt Damon
Address = 465 Ripley Boulevard, Oscar Mansion, Singapore 7666322
DOB = 10-10-1970
Phone Number = 790-3233
Account Balance = 405600.00
Account Type = Fixed
Fixed Daily Interest = 0.05
Account Id = 126
Name = Ben Affleck
Address = 200 Hunting Street, Singapore 784563
DOB = 25-10-1968
Phone Number = 432-4579
Account Balance = 530045.00
Account Type = Saving
Account Id = 65
Name = Salma Hayek
Address = 45 Mexican Boulevard, Hotel California, Singapore 467822
DOB = 06-04-73
Phone Number = 790-0000
Account Balance = 2345.00
Account Type = Checking
Account Id = 78
Name = Phua Chu Kang
Address = 50 PCK Avenue, Singapore 639798
DOB = 11-08-64
Phone Number = 345-6780
Account Balance = 0.00
Account Type = Checking
Account Id = 234
Name = Zoe Tay
Address = 100 Blue Eyed St, Singapore 456872
DOB = 15-02-68
Phone Number = 456-1234
Account Balance = 600.00
Account Type = Saving1) When you post code, please use[code] and [/code] tags as described in Formatting tips on the message entry page. It makes it much easier to read.
2) Don't just post a huge pile of code and ask, "How do I make this work?" Ask a specific question, and post just enough code to demonstrate the problem you're having.
3) Don't just write a huge pile of code and then test it. Write a tiny piece, test it. Then write the piece that will work with or use the first piece. Test that by itself--without the first piece. Then put the two together and test that. Only move on to the next step after the current step produces the correct results. Continue this process until you have a complete, working program.
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