Spanning Tree - Dealing With Static Variables

Feb 20, 2014

I'm new to Java and I'm trying to create a spanning tree in the desired order with 4 nodes (0,1,2,3). I've got the following code:

import java.util.ArrayList;
public class A {
public static boolean any(ArrayList<Integer> input) //To check for if any element in the ArrayList == 1
{
boolean answer = false;
for(int i=0;i<input.size();i++) {
if(input.get(i)==1)

[Code] ....

What happens is that the input parameter adj and hence the original adjmat inside main gets changed everytime I enter the method "connected", and I don't want this to happen. I understand that this is due to the main method being static and hence adjmat becomes static as well, but how do I change the code such that adjmat only gets modified after coming out of the connected function, and not while inside it?

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Find Minimum Spanning Tree Java

Mar 20, 2015

I am using the following code: But doesn't work fine. I try to find the Minimum spanning and print it out from house to which hose.

public class MinimumSpanning {
public static void main(String[] args) {
// [][] edge= are price between each hose edgs.
int [][] edge= {{0,7,9,12,0,0,0},
{7,0,0,10,0,0,0},
{10,0,0,12,0,0,0},
{12,10,12,0,11,0,10},
{0,0,0,11,0,4,8},
{0,0,0,0,4,0,6},
{0,0,0,10,8,6,0}};

[code]....

It should only print one time. Example between K to L prints many time.

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Why I can create an Instance of a class that contains non static variables within the static main method ?

This program runs fine

import java.util.*;
public class Test{
public int j;
public static void main(String[] args) {
Test test1=new Test();
System.out.println(test1.j);

[Code] .....

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Feb 11, 2014

I'm doing in this small piece of code -

JavaApplication3.java

package javaapplication3;
public class JavaApplication3 {
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int xlocation;
int ylocation;
String name;
static int ccount = 0;

[Code] .....

When I'm trying to compile it with netbeans i get these errors and i just can't figure why is that!

C:UsersuserDocumentsNetBeansProjectsJavaApplication3srcjavaapplication3JavaApplication3.java:16: error: Illegal static declaration in inner class JavaApplication3.robot
static int ccount = 0;
modifier 'static' is only allowed in constant variable declarations

C:UsersuserDocumentsNetBeansProjectsJavaApplication3srcjavaapplication3JavaApplication3.java:30: error: non-static variable this cannot be referenced from a static context
robot firstrobot = new robot(34,51,"yossi");

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Aug 6, 2014

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Can I follow any other approach other than using static object SET in servlets??

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import java.util.*;
public class calendar2 {
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}
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Oct 22, 2014

Say I have a class called ClassA which I want to hold my data. Now inside ClassA want to hold instances of a class lets call ClassB. So far we are here.

import blah.B
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private B myB;
(Getters setters etc)
public String getBString() {
B.getString();
}
}

However I want to have multiple extensions of ClassB which have UNIQUE static variables.

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private static String mString;
private static int mInt;
}

The problem I have run into is I can't have subclasses with their own static variables. I need the A class to hold any type of B class. How can I manage this?meant

public String getBString{
return B.getString();
}

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Feb 19, 2011

I thought static methods could never use instance variables, because they wouldn't know which instance to look at.

From Head First Java, p. 284: "A static method is not associated with a particular instance - only the class - so it cannot access any instance variable values of its class. It wouldn't know which instance's values to use."

Now I was answering some mock exam questions from Cameron McKenzie's SCJA book, and I don't understand one of the options. On page 205, the last question has an option that says: "Instance variables ... are not visible in static methods, unless passed in as arguments." This option is supposed to be correct. Now... how does that work?

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Sep 24, 2014

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Jun 17, 2014

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Oct 4, 2014

I am working with jsoup right now and I am trying to get a range of file extensions such as doc, docx, txt, pdf, and so on. Anyways i have looked through the jsoup api and cant seem to find what I am looking for. The closest thing I have found is

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This should work but only grabs one extension. How to grab multiple at one time? My guess would be:

Elements files = doc.select("a[href$=.doc]").select("a[href$=.docx]").select("a[href$=.txt]");

However I'm not sure for certain. Anyways I will provide a link for the api .....

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Apr 11, 2014

I am trying to solve involves an object array each object has two instance variables, a string(origin) and a double(price), that was originally unsorted I have already sorted the array. There are a total of 11 possible origins and 6 prices, so obviously some origins share prices with others. The array is sorted by origin alphabetically ignoring case. I now have to write to a file how many instances of each origin there is, tally up all the prices for each origin and a total for all prices. I get bonus points for utilizing the presorted array to my advantage for the final output and calculations.

It would be easy to write a branching statement and tally up all the origins and prices etc... However this is a linear operation and doesn't seem to benefit from the presorted array at all so I came up with what I think is a descent alternate solution.

I was thinking that I could go through the array one object at a time and stop when I came to an origin of the next type. For example: there are 12 names called "Adam" and then a name called "Bob". So if I stop at bob, check the index and add 1 then I know how many Adams there were. I can then continue this process with all the other names, all the while calculating the combined prices and all.

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Aug 3, 2014

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Also, I renamed a lot of variables via some suggestions and the assignments states "Make sure to write the appropriate constructors, getters, setters, toString and other methods as required for both classes." I think they're appropriate. Should I change some of he methods to better getters and setters identifiers?

Here is my code.

import java.util.Random;
public class CardsGameTest {
//execute application.
public static void main(String[] args) {
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[code].....

The instructions also say to "print each card as it is dealt" does that mean 5 cards one at a time? Anyways, I was thinking that in the driver class I could add a for loop to the for loop and as it deals a card it could run through the second for loop and print how many cards are left in the deck.

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This is an older version of what I'm doing currently, but it had the same basic problem with spaces.I will say I did my current version entirely different.

nner user_input = new Scanner (System.in);
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[Code] .....

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Oct 29, 2014

You should write a class that represents a circle object and includes the following:

1. Private class variables that store the radius and centre coordinates of the object.
2. Constructors to create circle objects with nothing supplied, with just a radius value supplied and with a radius and centre coordinates supplied.
3. Public instance methods that allow the radius and centre coordinates to be set and retrieved (often known as set/get methods).
4. Public instance methods that return the circumference and area of the circle.
5. A public class method that tests if two circle objects overlap or not

Here is my code:

import java.lang.Math;
public class Circle {
private double xCentre, yCentre, Radius;
// constructors
public Circle() {
xCentre = 0.0;
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[Code] ....

The second program just has to demonstrate each aspect addressed in the brief I pasted at the top.s of what else I can do.

This is as far as I got during the 3 hour lab session I had and both compiled fine but when running just displayed all the text eg. "Circumference of first circle is ", but didn't display any numeric values. I don't have the facilities to actually run the program unless I'm in the computer lab, I have a short opportunity to go in tomorrow but that will be the last so I'm doubtful that I'll get it fully working in time.

The problem is that when this code runs it doesn't display any numerical values, ie nothing is being passed between the two programs.

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@Post
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Apr 26, 2015

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The error is coming from:

public void updateDetailsPackage() {
some unrelated code
long zero=0;
double endUserCharge=0;
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[Code] ....

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May 26, 2015

Alright, I have two classes, this one

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}
private int strength;
private int defense;

[Code] .....

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Mar 15, 2015

I am trying to call an actionListener which is shown below in my PSVM :

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getContentPane().removeAll();
createPanel();
getContentPane().add(panel1); //Adding to content pane, not to Frame
repaint();
printAll(getGraphics()); //Extort print all content

[Code] .....

I get the following error :

Frame.java:409: error: non-static variable this cannot be referenced from a static context
menuItem1.addActionListener(new testMenuItemListener());

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Mar 3, 2015

I am trying to add a field (called special) to a hibernate table. I am copying existing code (related to the NAME field) so I don't have to figure this out from scratch. I am getting the error

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package com.voxware.impl.flow;
import com.voxware.asset.LiabilityType;
import com.voxware.flow.FlowConfiguration;
import com.voxware.flow.OrderFlow;
import com.voxware.flow.Step;
import com.voxware.i18n.LanguageCodes;
import com.voxware.impl.i18n.UTF8Control;
import com.voxware.impl.persistence.BaseEntity;
import com.voxware.impl.portal.VoxPortal;

[code]....

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Jul 27, 2014

I'm working on a banking program that is supposed to use 3 classes (Account-base class, CheckingAccount, and SavingsAccount) and several methods to display the banking information (ID, balance after a withdrawal and deposit, and the annual interest rate). This should be a pretty simple program, but I'm getting hung up on one portion of it. I'm getting some compiler errors, all of which deal with non-static variables being called from a static context (I'll also post these errors following the code). Up until the middle of last week, we just declared everything as static, but that's changed and I'm having trouble figuring out when to and when not to use static when declaring my methods, hence the compiler errors.

import java.util.Date;
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private int id = 0;
private double balance = 0;
private double annualInterestRate = 0;
private Date dateCreated = new Date();

[Code] ....

Here are the compiler errors I am receiving:

Compilation completed. The following files were not compiled:
6 errors found:
File: C:UsersHiTechRedneckDesktopSummer II 2014Computer Programming PrincipleProgram 5CheckingAccount.java [line: 7]
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[Code] .....

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Mar 14, 2015

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[Code] .....

I get the following error :

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Apr 27, 2014

I am writing the following program in Java SE 7. It throwing "Cannot make a static reference to the non-static type String" . However if I write parameterised String inside main method as  java.lang.String[] args, it compiles fine.
 
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  <T> MainClass(T t) {
   System.out.println(t.getClass().getName());
  } 
  public static void main(String[] args) {
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}
 
I mean following programs compile fine in Java SE 7 :
 
class MainClass<String> {
  <T> MainClass(T t) {
   System.out.println(t.getClass().getName());
  }
  public static void main(java.lang.String[] args) {
  System.out.println("asdasd");
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Aug 19, 2014

i am trying to make something, and i want to request input from user and it shoud look like this

1. xxx -> press 1 to choose this
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So if they enter 3 or string or whatever i want to restart method and show again

1. xxx -> press 1 to choose this
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[code]....

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