Java Linked List
public class outlier2D
double cord[];
int dim ;
outlier2D next;
outlier2D()
next=null;
void create_Dim(int k)
cord=new double[k];
public static void main(String args[])
double[] iLine = new double[dim];
outlier2D curr=null;
outlier2D node1=null;
while(((record = br[0].readLine()) != null))
iLine[0] = new Double(record).doubleValue();
iLine[1] = new Double(br[1].readLine().trim()).doubleValue();
outlier2D newobj=new outlier2D();
newobj.create_Dim(dim);
newobj.cord=iLine;
if(node1==null)
node1=newobj;
curr=newobj;
else
curr.next=newobj;
curr=curr.next;
The "node1" and "curr" are 2 objects to the class "outlier2D" which is supposed to be the List class.node1 is the head object. When i access the value for node1 in the if statement i get the first value as the result.
But when i access the value outside the while loop after inserting all the data,my head object moves to the last data.........
I would appreciate if anybody could help me with this as i have been trying to find this from past 2 days.
Thank you
Your creation of the linked list appears to be correctly coded. However, you appear to have a few other problems.
1) You haven't set dim.
2) Is outlier2D your main class? If so your main(String [] args) method is outside of any class. Just a typo?
3) (And this is probably the root of your problem.) Every instance of your outlier2D class has cord set to iLine! You go to the trouble of creating a new double array in your create_Dim(int k) method and setting cord to point to it but then replace it in your while loop by setting cord to point to iLine.
Remember that arrays are Objects and the name of the array is a pointer to the object. By writing:
newobj.cord = iLine;
you are setting every instance of cord to point to the same instance of iLine.
Similar Messages
-
Hey,
I am having trouble understanding the Linked List implementation code given under the Node Operations part of this pdf.
http://www.cs.berkeley.edu/~jrs/61b/lec/07.pdf
public ListNode(int item, ListNode next) {
this.item = item;
this.next = next;
public ListNode(int item) {
this(item, null);
ListNode l1 = new ListNode(7, new ListNode(0, new ListNode(6)));
I understand the earlier implementation, but this one has me confused. Would someone please go through/explain the flow of this implementation with me?
ThanksWell the code is pretty self explanitory.
a ListNode class that has two fields. an int field item, and a ListNode field next.
so when you create a ListNode object you can do so by one of two means passing one parameter or passing two parameters.
if you pass one parameter then you have a ListNode which has an int say 1 and a ListNode object who's value is null.
if you pass two parameters then you have a ListNode which has an int say 2 and a ListNode object who's value is the ListNode you pass to it.
ex ListNode myNode = ListNode(1,new ListNode(2));
so myNode now has an integer 1 and a reference to another ListNode which has an integer value of 2 and a reference to a null ListNode.
hope this helps. -
how do i actually go about sorting a linkedlist using bubble sort. i have tried to move the data to an array than use a bubble sort to sort the array but the java application give me a java null pointer exception
here is the part where i pass in the array for the bubblesort to sort the data.
while ((txt=bfr.readLine())!=null){
// break the string up into tokens
st = new StringTokenizer(txt,",");
int i = 0;
while (st.hasMoreTokens()){
s[i++] = st.nextToken();
//System.out.println(s[1]);
ll.add(s[1]);
ll.toArray(arr);
System.out.println(arr[0]);
bs.sort(arr);
this part of the bubble sort give me an error it say java.lang.null poiner exception at the[u] .compareTo & also at the top part of the code where i call fro the bs.sort(arr);// sort the array
while (doMore) {
n--;
doMore =false; //assume this is our last pass
for (int i=0; i<n; i++) {
int result = x.compareTo(x[i+1]);
if (result > 0) {
String temp = x;
x[i] = x[i+1]; //swap
x[i+1] = temp;
doMore = true; // must repeat after swap -
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. -
Not to hard for you java types. Simply creating a doubly linked list.
How do i go about declaring a doubly linked list and add nodes to it?
see http://java.sun.com/j2se/1.3/docs/api/java/util/LinkedList.html
which is implemented as a doubly linked list:
import java.util.*;
public class ListTest {
public static void main(String [] argv) {
// synchronize if multiple threads are using list
LinkedList list = Collections.synchronizedList(
new LinkedList());
list.addFirst("this");
list.addLast("is");
list.addLast("a test");
ListIterator it = list.iterator(0);
// with iterator you can walk the list
}You can then use iterators to walk the list:
http://java.sun.com/j2se/1.3/docs/api/java/util/ListIterator.html
Good Luck. -
Search in Double link list in java
Can any body give me the code implementation for searching an element in double link list in java as soon as possible...
Can any body give me the code implementation for
searching an element in double link list in java as
soon as possible...Psuedo code...
current = head of list
found = null
while(current is not null)
if doesItMatch(current, target)
break
current = current->next
if (current is null) Out("no match")
else Out("found it") -
New to java -especially linked lists
I�m trying to work with linked lists but not having much luck�
Overall, the program must create a datastructure that will hold titles of articles. Up to 10 keywords can be added to each article and it must then be possible to search all of the titles for matches to the keyword.
Currently I�m stuck in a for-loop � my linked list (articleList) is not accepted. Any help would be much appreciated. The following error occurs when I attempt to compile:
SearchMachine.java:30: cannot resolve symbol
symbol : variable articleList
location: class SearchMachine
for(ListIterator listiter = articleList.listIterator(); listiter.hasNext();)
^
import java.util.*;
class Document
private String title;
private String keywords [] = new String [10];
private int last = 0;
public Document (String _title)
String title = _title;
public void addKeyword(String kw)
if(last < 9)
keywords [last]= kw;
last ++;
System.out.println("The keyword " + kw + " has now been added");
else if (last == 9)
keywords [last]= kw;
System.out.println ("The document now has 10 keywords. No more can be added");
class SearchMachine
SearchMachine()
LinkedList articleList = new LinkedList ();
articleList.add (new Document ("Oracle 8 the new SQL programming"));
articleList.add (new Document ("Java programming made easy"));
public void print()
for(ListIterator listiter = articleList.listIterator(); listiter.hasNext();)
System.out.println(listiter.next());
public static void main (String [] args)
SearchMachine search;
search = new SearchMachine();
search.print();This is a basic scope issue. You declare the variable articleList inside the constructor block and thus it's visible only in the constructor block. The variable doesn't exist anywhere else but in SearchMachine() {...} The solution is to move the line "LinkedList articleList = new LinkedList();" three lines up, outside the constructor but inside the class definition, so that articleList becomes a member of the SearchMachine class.
-
Delphi Double Linked List to Java
Does a Delphi Double Linked List correspond to any data type in Java?
Thanks for your time,
NateLook at the documentationf for java.util.*, in particular the collections therein.
java.util.LinkedList is probably closest to what you want. -
How can we write the program for Doubly Link List in java?
Please give program with detailed explanation.You may want to post this on Java forums at:
http://forum.java.sun.com/forum.jspa?forumID=24
http://forum.java.sun.com/index.jspa
I found the following threads that may be of use:
http://forum.java.sun.com/thread.jspa?forumID=256&threadID=196730
http://forum.java.sun.com/thread.jspa?forumID=24&threadID=619245
Also: an example at http://www.sourcecodesworld.com/articles/java/java-data-structures/Doubly_Linked_Lists_with_Enumeration.asp -
Problem with Queue and linked list
Hi... i've got an assignment it start like this.
You are required to write a complete console program in java includin main() to demonstrate the following:
Data Structure: Queue, Priority Queue
Object Involved: Linked-List, PrintJob
Operations Involved:
1. insert
2. remove
3. reset
4. search
Dats all... I've been given this much information... Can any1 try to help me please... How to make a start??? And wat does the print job means???
Can any1 tell me wat am supposed to do...Hi,
Why don't you start your demo like this?
import java.io.IOException;
public class Demo {
public Demo() {
public void startDemo() throws IOException {
do {
System.out.println("String Console Demo ");
System.out.println("\t" + "1. Queue Demo");
System.out.println("\t" + "2. PriorityQueue Demo");
System.out.println("\t" + "3. LinkedList Demo");
System.out.println("\t" + "4. PrintJob Demo");
System.out.println("Please choose one option");
choice = (char) System.in.read();
showDemo(choice);
} while (choice < '1' || choice > '4');
public void showDemo(char ch) {
switch (ch) {
case '1':
System.out.println("You have chosen Queue Demo ");
showOperations();
break;
case '2':
System.out.println("You have chosen Priority Queue Demo ");
showOperations();
break;
case '3':
System.out.println("You have chosen LinkedList Demo ");
showOperations();
break;
case '4':
System.out.println("You have chosen Print Job Demo ");
showOperations();
break;
private void showOperations() {
System.out.println("Please choose any operations ");
System.out.println("\t" + "1. Insert ");
System.out.println("\t" + "2. Remove ");
System.out.println("\t" + "3. Reset ");
System.out.println("\t" + "4. search ");
public static void main(String[] args) throws IOException {
Demo demo = new Demo();
demo.startDemo();
private char choice;
Write a separate classes for the data structures show the initial elements and call the methods based on the operations then show the result.
Thanks -
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 -
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. -
How can you create a linked list? GUI?
I have the following program that I wrote:
package damagecounter;
import java.io.*;
import java.util.*;
public class Main
public static void main (String[] args) throws Exception
String logline;
Player player1 = new Player("Kazzandar");
try
BufferedReader logfile = new BufferedReader(new FileReader("TeilmonRun.txt"));
logline = logfile.readLine();
while (logline != null)
if (logline.startsWith (player1.getName (), 0))
if (logline.contains ("recites"))
player1.recites++;
if (logline.contains ("rescues"))
player1.rescues++;
if (logline.contains ("utters the words"))
player1.spells++;
if (logline.contains ("sprawling with a powerful bash."))
player1.bashes++;
if (logline.contains ("got toasted by"))
player1.deaths++;
if ((logline.contains ("-=")) && (logline.contains ("=-")))
if (logline.startsWith (player1.getName (), 0))
String damage = logline.substring(logline.indexOf ("-=") + 2 , logline.indexOf ("=-"));
player1.setDamage (Integer.parseInt (damage));
logline = logfile.readLine ();
catch (Exception e)
System.out.println ("Log file not found or corrupt.");
e.printStackTrace();
player1.printStats();
}As of right now the code require a person to enter the name of a player and then scans the log file to determine the appropriate counts for that player. If I want to scan the file for multiple players how would I be able to do that without having to run the program over and over. The reason being that sometimes the logs have over 15 different players and I'd hate to have to run the program 15 times to get each players stats. Any suggestions? Would I have to make a linked list?Yes, the log file looks something like that. Here is a small 15 line version of what the log file actually looks like:
Kazzandar's stab misses Icingdeath. -=0=-
Arien's slash >>> ANNIHILATES <<< Icingdeath! -=118=-
Arien's slash >>> ANNIHILATES <<< Icingdeath! -=112=-
Arien's slash <<< ERADICATES >>> Icingdeath! -=158=-
Parrish utters the words, 'yjrr pzar'.
Arien rescues Shargaas!
Kazzandar's counterattack does UNSPEAKABLE things to Icingdeath! -=636=-
Icingdeath's claw does UNSPEAKABLE things to Arien! -=760=-
Arien's fireball scratches Icingdeath. -=4=-
Arien's lightning bolt grazes Icingdeath. -=7=-
Arien's counterattack -- DESSICATES -- Icingdeath! -=540=-
Icingdeath's claw COMPLETELY TRASHES Arien! -=802=-
Arien is DEAD!
Kitiara's fireball grazes Icingdeath. -=5=-
Kitiara's lightning bolt grazes Icingdeath. -=8=-
Almost always the player name is first but sometimes the "mob" name (In this case Icingdeath) comes out. I don't mind if Icingdeath is referenced as a player and included in the stats, not that big a deal. Thanks for the idea on the HashMap I'll looking into how it works. Since this is my first Java program I often find myself lost at where to begin.
I changed "got toasted by" to "is DEAD!" since it's easier to read. I also changed the majority of the main code into a method for the player class. The main code looks like this now:
public static void main (String[] args) throws Exception
Player player1 = new Player("Shargaas");
player1.scanLogForStats("TeilmonRun.txt");
player1.printStats();
I was hoping this would make it easier, anyway, thanks again and I'll definitely be looking into HashMap. -
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? -
I am confused at how to make a linked list using recursion. I've been looking at the syntax and examples from the web for the past couple hours, but all seem to be based on an empty .java file. I need to put it in my code somehow. here's the code segment:
public static boolean RecursiveTest (String s, int start, Node n) {
// The linked list
Node<char> bracket = new Node<char>();
int size = s.length();
char v = s.charAt(start);
//String sElement = parens.top();
boolean isGood = true;
// ending "ifs"
if (size == 0) { System.out.println("empty string"); return false; }
if (start == size) return isGood;
if (s.charAt(start) == '(' || s.charAt(start) == '[' ||
s.charAt(start)== '{') {
v.Push(sChar);
System.out.println(sChar);
return RecursiveTest(start+1, s.charAt(start));
else if (sChar.equals(")") && sElement.equals("(")) {
parens.Pop();
System.out.println(sChar);
return RecursiveTest(start+1);
else if (sChar.equals("]") && sElement.equals("[")) {
parens.Pop();
System.out.println(sChar);
return RecursiveTest(start+1);
else if (sChar.equals("}") && sElement.equals("{")) {
parens.Pop();
System.out.println(sChar);
return RecursiveTest(start+1);
else if (sChar.equals(")") && !sElement.equals("(")) {
System.out.println("bad");
isGood = false;
return isGood;
else if (sChar.equals("]") && !sElement.equals("[")) {
System.out.println("bad");
isGood = false;
return isGood;
else if (sChar.equals("}") && !sElement.equals("{")) {
System.out.println("bad");
isGood = false;
return isGood;
else return RecursiveTest(start+1);
} // end of RecursiveTest
I'm passing a string, 0, and a new node (i dunno about the last one there), from an above main class.
This code is wrong, i know, but it's all I got done so far. How would I be able to make a linked list inside this method?No one knows how to do a linked list inside a recursive method?Yes we do, but you have to realize that a list (whether it be a linked list
or an array list or whatever) has nothing to do with recursion per se.
If that list has to keep track of some state it certainly mustn't be created
within that recursive method as a local variable. And (see my previous
reply), what do you need recursion for? Counting and pairing brackets
can easily be done using an iterative method where the list keeps track
of the last seen left bracket (of any type).
kind regards,
Jos
Maybe you are looking for
-
Hi, I have a iMac pedestal version which has worked great for years, however the screen just died. I thought about connecting the computer up to another monitor or TV so wanted a connector. I bought a mini-DVI to VGA connector but it's the wrong part
-
Constant error message, Need Help!
New to flash CS3, everytime i try to save or publish or even sample i get an error... Error Signature AppName: flash.exe AppVer: 9.0.0.494 ModName: flash.exe ModVer: 9.0.0.494 Offset: 00c5958f I could appriciate it if anyone could help me...
-
Hi, I have a customer who is using two nearly identical workstations for Adobe Premiere CS5. Both are running Win7 64bit with 12GB of ram, i7 quadcore cpu and a mix of SSD and HDD drives. Both are also using the Nvidia GTX graphic cards & CS5 acceler
-
Adding update control to new Movement Types
Hello all; I have a requirement to create a movement to allow customer consignment receipt from a finished goods purchase order. So I used OMJJ to copy the 101 movement type to Y01 which seemed to work OK, but I need to make an entry in the section l
-
Hi there, Happy Holidays.....Need help here.
I actually came to Brazil to spend holidays with my family and I wonder if I use my smart phone to browse the internet, use skype, text message to talk to my firends in US while I am here by using the Wi-Fi service at hotel, will I get charged extra