Invoking Subclass Method On Object In A Linked List

Apr 9, 2014

I am trying to put a reference to a given subclass object into a linked list, and then come back later, and invoke a method of the subclass object that is in a given spot in the linked list. This produces an error because Object does not have that method. Is it necessary to cast the object to the correct subclass every time I want to use one of its methods, or is there a way to convince the JVM to treat it as always of type MySubclass?

View Replies


ADVERTISEMENT

Public Method That Takes Array Of Type Object To Load Strings Into Linked List

Oct 13, 2014

I am having a little trouble with a part of my Java assignment that needs to have linked lists in it.

I need to write a public method that takes an array of type object to load strings into a linked list.

View Replies View Related

Sort Linked List Through The Nodes Of List - Data Of Calling Object

Feb 14, 2014

I have some class called sorted to sort the linked list through the nodes of the list. and other class to test this ability, i made object of the sort class called "list1" and insert the values to the linked list.

If i make other object called "list2" and want to merge those two lists by using method merge in sort class. And wrote code of

list1.merge(list2);

How can the merge method in sort class know the values of list1 that called it as this object is created in other class.

View Replies View Related

Searching For Object In Linked List Then Removing The Object

Nov 19, 2014

I have just started working with linked lists. I have a linked list of Objects and I want to be able to search for a specific object. But currently my code continues to return false. Also how would I go about removing the first index of the linked list.

public static void main(String[] args) {
LinkedList<Cookies> ml = new LinkedList<>();
int choice = 0;
while (choice >= 0) {
choice = menu();

[Code] ....

View Replies View Related

Insert Method Of Linked List

Dec 30, 2014

Is there a particular implementation of a linked list you are referring to in your question?

View Replies View Related

Implement Add Method For Singly Linked List

Apr 26, 2015

Implementing the add(int i, E o) method for a SinglyLinked List.

public void add(int i, E o)
// pre: 0<=i<= size()
// post: adds ith entry of list to o

View Replies View Related

Substring Method And Singly Linked List

Jul 16, 2014

I'm still working with the singlylinkedlist data structure and trying to return a string of individual characters stored in each node. ( head--('J')---('A')---('V')---('A')---tail ) Hopefully this beautifully executed depiction to the left will clarify.

This is what I came up with after designing the algorithm w/ pen and paper. I know that I'm not accounting for the OutOfBound errors, an empty list, or an index < 0.... I will get to that.

Right now, I'm not sure why my assignment to the character array, ' chars[i] = cursor.getLink(getElement()); ' , is not working. The two methods getLink and getElement, type Node and T, respectively, exist in my Node class which is a private nested class in MySLList. Why would I be getting the following error: "The method getElement() is undefined for the type StringX" ? Is this a good design and implementation of the substring method?

public String substring(int index) {
char[] chars = new char[(getSize() - index)]; //getSize() defines the size of list in MySLList
Node cursor = null;
//Set the cursor to the node = index
if(cursor == head) {

[Code] ....

View Replies View Related

Linked List Queue ToString Method

Oct 21, 2014

So I have to write all the methods for a LinkedListQueue. I've got isEmpty, enqueue and dequeue working correctly (I think) but I'm having trouble with the toString method. I tried to do it recursively and it works if there is only one element in the list, but with multiple elements it throws a StackOverflowerror exception. I've tried it multiple different ways, but I can't seem to figure out how to print it out with out clearing everything. We haven't been taught StringBuilder or .append yet, which I saw a lot of as I was looking for solutions, so I can't use those.

public class LinkedQueue<T>
{
protected LLNode<T> front; // reference to the front of this queue
protected LLNode<T> rear; // reference to the rear of this queue
private T info;
public LinkedQueue()
{
front = null;
rear = null;

[Code] ....

and this is the ITD used with it, for some reason it has the "empty the queue" function as a choice but we weren't assigned that function, so just ignore it.

import java.util.Scanner;
public class ITDLinkedQueue
{
public static void displayMenu()
{
System.out.println("(1) display menu");
System.out.println("(2) check isEmpty");
System.out.println("(3) enqueue");
System.out.println("(4) dequeue");

[Code] ....

View Replies View Related

Writing IndexOf Method For More Than One Instance In A Linked List

Jun 7, 2014

I'm trying to write an indexOf() method that will return every time a value occurs in a linked list. I need to use my user-created linked list not the built in Java linked list. For example in a linked list of characters: "i, p, z, z, n, d, p, z" when I search for "z" it should return position variables for 3, 4, and 8. Currently what I have is obviously only returning the first instance.how I can return more than one instance?

public int indexOf(char input) {
LLNode currentNode = this.first;
int position =1;
boolean found = false;

[code]...

View Replies View Related

Method That Print Data Of Single Linked List Backward Using Stack

Apr 23, 2015

I am trying out solving the question but i am stuck.The problem is to write a method that print data of single linked list backward using stack.The question is as follow

public class Stack{
public boolean isEmpty(){};
public void push(int n){};
public int peek(){};
public int pop(){};
}

public class node{
int data;
node next;
}

public class list{
node first;
}

View Replies View Related

Dice Game - Invoking Method In Other Method Of Same Class

Feb 26, 2015

I am currently working on a dice game. I have a private method called rollDice and it performs the action of rolling two dice. For my project, I need to create another method called playerRolls and I am supposed to invoke the rollDice method in the playerRolls method and perform actions based off of that. My question right now is how do I invoke a method into another method of the same class?

View Replies View Related

Invoking Non-Existent Method - Matching Parameters To Method

Oct 17, 2014

Java-code, When i compile the java doc. I get output;

Perceptron.java:12: learn(Instance[],int,int) in Perceptron cannot be applied to (Instance[],int)
PerceptronModel model = learn(train_data,5);
^
1 error

And here is the code

import java.io.*;
public class Perceptron {
public static void main(String[] args) throws IOException {
DataReader reader = new DataReader();
reader.init(args);

[Code] ....

View Replies View Related

Invoking Static Method With Array

Apr 16, 2015

I'm writing a code with a cellphone class to set price, brand and serial number. I'm also, in the main method, initializing 100 different cellphone in a matrix style ( up to here I'm fine). I have to use a copy constructor to define some cellphones ( fine too). Another thing I had to do was to generate random numbers and swap the price of the cellphones ( which I'm fine with too). My problem lies in my static method. I coded it all, but I can't seem to invoke it on the cellphone.

Basically, the method has to search for cellphones in the array with the same price, swap the price, print it out, and keep a counter of the price swap it has made. But I can't seem to invoke it on eclipse. It keeps telling me it is undefined for the class cellphone ( the method modifyCellPhone)

Here's the code:

import java.util.Random;
class Cellphone {
private String brand;
private long serialNumber;
private double Price;
public Cellphone (String br, long sN, double Pr) {

[Code] .....

View Replies View Related

Polymorphism / Dynamic Binding - Invoking Wrong Method

Jan 9, 2014

Why is the equals-method in the super-class invoked? Shouldn't the equals-method in the sub-class be invoked(at least in the first if-statement since b2 is a B(i know B is also an A))?Is the equals-method overridden? Or does B have its own equals-method?

class SomeClass{
public static void main(String[] args) {

B b1 = new B(123,1);
B b2 = new B(123,2);

[code]...

View Replies View Related

Can't Run Method FindSmallest In Subclass NEW

Apr 21, 2015

I'm having a difficult time running this piece of my program. I can't run the method findSmallest() in subclass NEW because I receive an error that says I have to declare the variable "smallest" as final, but then I won't be able to continue my code because "smallest" when I happen to use "smallest" again, it will always be set to 0.

package FindYourCourseGrades;
import java.util.Scanner;
public class FindYourGrades {
public static void main (String[] args){
int number = 0;
int counter = 0;
int sum = 0;
double average = 0;
double smallest = 0;
 
[code]...

View Replies View Related

Linked List Implementation Of List Interface?

Oct 5, 2013

So we have an assignment regarding a linked list implementation of a given list interface.

In my list interface, the method contains(T anEntry) is defined.

In the LList implementation, contains is already implemented as part of getting the core methods in.

Now I am being tasked with the following:

Provide a second implementation of the method contains2(T anEntry) that calls a private recursive method

Private boolean contains (T anEntry, Node startNode) that returns whether the list that starts at startNode contains the entry anEntry.

I've written the private recursive method already. That's not an issue (at least not right now).

But what I don't understand is how startNode is supposed to be populated when this private contains method is called from the public contains2 method? contains2 only takes one parameter: anEntry. the private method takes two parameters: anEntry and startNode. How am i supposed to provide startNode when I am calling contains2?

View Replies View Related

List Interface Class That Has Operations For Linked List And LList Class

Oct 6, 2014

I have this ListInterface class that has operations for my linked list and a LList class. The Llist and ListInterface classes are perfect. My job is to create a driver, or a demo class that showcases these operations. That being said, heres the driver so far:

import java.util.*;
public abstract class DriverWilson implements ListInterface
{
public static void main(String[] args)
{

LList a = new LList();

[code]....

View Replies View Related

Inserting A Set Into Linked List?

Mar 21, 2014

What I'm supposed to do is make a method to insert a set of Tiles to the list,i.e.,a detour(make sure that the inserted detouris compatible with thecurrent path so that the resultingpathdoesnot have any gaps). But I'm confused on how to go about doing it. I was thinking of maybe just adding 1 to the current Node.

import java.io.File;
import java.io.FileNotFoundException;
import java.util.List;
import java.util.Scanner;
public class Path {
static Tile startTile;

[code].....

View Replies View Related

Dynamic Linked List

Jan 30, 2014

I'm trying to implement an Office class that contains an inner class: WorkerNode. The WorkerNode class has a name attribute (String) and WorkerNode attributes for boss, peer and subordinate. The attributes of Office are manager and current which are WorkerNode references. The manager refers to the entry point of the structure and current is the current node in the structure. For simplicity, i'm going to try to limit it to 3 levels and assume that the names are unique. I've put together a Office class that containing main and provided the code I've worked on so far.

public class Office {
public static void main(String[] args) {
String name=Input.getString("input the manager's name: ");
Office office=new Office(name);
int option;

[code]....

View Replies View Related

Linked List Sorting

Apr 20, 2014

I have made a node class and im trying to implement a sorting method. I must use a selection sort but with specific instructions: "Your method should not need to use the new operator since it is just moving nodes from one list to another( not creating new nodes)

this is my current implementation ..but i am instantiating new object..

public class NodeInt
{
private int data;
private NodeInt next = null;
public NodeInt(){}
//precondition:
//postcondition:
public NodeInt(int data, NodeInt next)
{
this.data = data;
this.next = next;

[code]....

edit: this is the part that worked but i had it commented out so i have the previous and current declared above but didnt copy.

View Replies View Related

Searching Linked List

Apr 30, 2014

Ok here I have a code that generates 1 million random values then converts them to a string then hashcode. I then insert into a linked list and then I want to run through each hash and find it in the linked list timing each run then averaging out the time at the end.

It works great for smaller amounts of numbers it is searching for (fine under 50 thousand searches for the for loop starting at line 24 LinkedListTest.java) but when I try to do the full million searches it gives me "a Exception in thread "main" java.lang.StackOverflowError" at line 158 in List.java. Maybe im getting tired but I cannot figure out why.

// class to represent one node in a list
class ListNode< T >
{
// package access members; List can access these directly
T data; // data for this node
ListNode< T > nextNode; // reference to the next node in the list

[code]....

View Replies View Related

Building Linked List Whose Nodes Data Is The Sum Of Nodes Of Other List

May 1, 2014

public void add(int d){
listNode l = new listNode (d, null);
l.next = first;
first= l;

public list Sum2List (list l1, list l2){
//variables
int sum;

[Code] .....

But I have a problem in my first listNode where it ll be pointing to null, thus in the sum2List method the program checks the while condition into false and doesn't go through the loop.

View Replies View Related

Get Object Strings To Print In List So That User Can Select That Object To Manipulate Its Attributes

Oct 7, 2014

I am new to Java and have read books, the Java docs, and searched the Internet for my problem to no avail. I have an Array of objects that contains strings. How can I get the object's strings to print in a list so that the user can select that object to manipulate its attributes? For example, the user can select "Guitar 1" from a list and manipulate its attributes like tuning it, playing it, etc. I have a class called Instruments and created 10 guitar objects.Here is the code:

Instrument [] guitar = new Instrument[10];
for (int i = 0; i < 10; i++) {
guitar[0] = new Instrument("Guitar 1");
guitar[1] = new Instrument("Guitar 2");
guitar[2] = new Instrument("Guitar 3");
guitar[3] = new Instrument("Guitar 4");
guitar[4] = new Instrument("Guitar 5");
guitar[5] = new Instrument("Guitar 6");

[code]...

View Replies View Related

Add Or Remove Will Be More Efficient By A Linked List

Jan 31, 2015

if one address point on another address. so set and get methods will be less efficient then an array, but add or remove will be more efficient by a linked list ? a linked list also inherit from queue so if i add an elemnt via "addFirst" function . where its adding the element ? to the right most or left most ?
if i have for example :

here [ ] --> [ ] --> [ ] --> [ ] -->[ ] or here

linked list its FIFO so the head will be the right most ?

Edit : its confused me a little bit but i understood now .so it will be at the left most. its actually ordered . not like the stack which is LIFO.

View Replies View Related

Sort Singly Linked List

Oct 30, 2014

I searched a lot but can't seem to understand the sorting of a SLLNode... I noticed a method called Bubble Sort, I understand how it works, but can't think of a way to implement it to my code..

View Replies View Related

How To Move Along A Doubly Linked List

Dec 11, 2014

I'm having some trouble with figuring out how to move along a doubly linked list for an assignment. The program is supposed to be a simple board game simulation. Here is what I have so far:

Space.java:

public class Space
{
private String name;
public Space next;
public Space previous;
public Space(String name)
{
this.name = name;

[Code]...

I seem to have been able to get all the other methods working properly, but I am pretty stuck on how to do the movePlayer. Specifically because it is passing an integer, but my objects are of type Space and Boardgame.

View Replies View Related







Copyrights 2005-15 www.BigResource.com, All rights reserved