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?
View Replies
ADVERTISEMENT
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.
View Replies
View Related
Oct 28, 2014
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] .....
View Replies
View Related
Feb 11, 2014
I'm doing in this small piece of code -
JavaApplication3.java
package javaapplication3;
public class JavaApplication3 {
public class robot {
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");
View Replies
View Related
Aug 6, 2014
Can we use static variables or static objects in servlets ?? I want to restrict same user to enter into the application from different system when the user is already working, he needs to get a message saying "User is already in use ".
I have created static SET object in LoginServlet and inside doget() I checked if SET contains user ,if yes display him above message otherwise add the user in SET object and forward it to next page . Later while logging out user is removed from SET .
Can I follow any other approach other than using static object SET in servlets??
View Replies
View Related
Oct 27, 2014
why using the get method(c.get(c.HOUR_OF_DAY)); gives me the correct hour(currently 19) but directly accesing c.HOUR_OF_DAY returns 11 ? It shows In the documentation that HOUR_OF_DAY is public.
import java.util.*;
public class calendar2 {
public static void main(String[] args) {
new calendar2().timer();
}
private void timer() {
Calendar c=Calendar.getInstance();
//c.clear();
System.out.println(c.get(c.HOUR_OF_DAY));
System.out.println(c.HOUR_OF_DAY);
}
}
View Replies
View Related
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
public class A {
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.
public class B-1 extends B {
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();
}
View Replies
View Related
Jan 22, 2015
Are the static variables in servlet thread-safe?
View Replies
View Related
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?
View Replies
View Related
Sep 24, 2014
a code to search for static variables that look like username or password.i want to be able to search through a source code for such variables.
View Replies
View Related
Jun 17, 2014
How to do draw the original binary tree based on traversal results?
A binary tree has this pre-order traversal result: A,B,D,H,I,E,F,C,G,K,J (TreeNodes) And the same tree gives the following in-order traversal: B,H,I,D,A,C,F,E,K,G,J. Can you draw the tree structure?
View Replies
View Related
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
Elements files = doc.select("a[href$=.doc]");
This should work but only grabs one extension. How to grab multiple at one time? My guess would be:
Elements files = doc.select("a[href$=.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 .....
View Replies
View Related
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.
View Replies
View Related
Aug 3, 2014
I redid my entire code to use array-lists instead of just arrays my professor finally got back to me and said he doesn't want us to use lists. The assignment is to create a CardGame driver class, then create a "card" in a card class, then a "deck of cards" in a DeckOfCards class, shuffle, and deal 5 random cards and "deal a card and report the number of cards left in the deck". That last line in quotes is what I do not know how to do.
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) {
DeckOfCards myDeck = new DeckOfCards();
myDeck.shuffle(); //shuffle cards.
[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.
View Replies
View Related
Oct 5, 2014
I am working on a small brain teaser project where I am taking a string input from a Scanner, and turning into ascii. The problem comes into play when the string has a space in it, so if the question is what's your name? and you say Michael Jackson, Michael gets converted then Jackson becomes the answer to the next question, rather then the second portion of the current string.
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);
//Creates a string
String favoriteFlick;
System.out.println("Enter the title of your favorite film?");
favoriteFlick = user_input.next();
[Code] .....
View Replies
View Related
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;
yCentre = 0.0;
Radius = 1.0;
[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.
View Replies
View Related
Mar 26, 2015
This is my code inside the method:
@Post
public static String getDetails(Representation entity) throws Exception {
String customerId = getQuery().getValues("cus_id");
}
I use this code in Restlet Representation. I try to get the value from the Request API. But I am facing the problem as "Cannot make a static reference to the non-static method getQuery() from the type Resource".
View Replies
View Related
Jun 27, 2014
From what i understand static methods should be called without creating an instance of the same class . If so why would they return an instance of the same class like in the following : public static Location locateLargest(double[][] a) , the Location class being the same class where the method is defined . I don't understand this , does it mean that every field and every method in the class must be static ? Meaning that you cannot have instances of the class because everything is static . Or it's just a mistake and the class Location cannot have a static method: public static Location locateLargest(double[][] a) ?
View Replies
View Related
Apr 26, 2015
I can't figure out what this error message "Cannot make a static reference to the non-static method getEndUserCharge(long, long, long, long) from the type UpdateUserWS" actually means.
The error is coming from:
public void updateDetailsPackage() {
some unrelated code
long zero=0;
double endUserCharge=0;
endUserCharge = UpdateUserWS.getEndUserCharge(long zero, long zero, long zero, long zero); <-------- error is here
[Code] ....
View Replies
View Related
May 26, 2015
Alright, I have two classes, this one
public class Player {
private String player;
public String getPlayer() {
return player;
}
private int strength;
private int defense;
[Code] .....
However, it says that under Player.getPlayer() that it 'Cannot make a static reference to the non-static method'.
View Replies
View Related
Mar 15, 2015
I am trying to call an actionListener which is shown below in my PSVM :
class testMenuItemListener implements ActionListener {
public void actionPerformed(ActionEvent arg0) {
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());
View Replies
View Related
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
"[ERROR] C:VOXvoxware-1.1.13voxwarevoxware-implsrcmainjavacomvoxwareimplflowVoxFlowConfiguration.java:[213,38] error: non-static variable special cannot be referenced from a static context".
Line 213 is in public void mergeFrom, the actual line is "special = VoxFlowConfiguration.special;" I don't understand why Java thinks special is a "non-static" variable but it doesn't have a problem with the other variables (such as name, orderShow)
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]....
View Replies
View Related
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;
public class Account {
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]
Error: non-static method getId() cannot be referenced from a static context
[Code] .....
View Replies
View Related
Mar 14, 2015
I am trying to call an actionListener which is shown below in my PSVM :
class testMenuItemListener implements ActionListener
{
public void actionPerformed(ActionEvent arg0) {
getContentPane().removeAll();
createPanel();
getContentPane().add(panel1); //Adding to content pane, not to Frame
repaint();
[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());
View Replies
View Related
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.
class MainClass<String> {
<T> MainClass(T t) {
System.out.println(t.getClass().getName());
}
public static void main(String[] args) {
System.out.println("asdasd");
new MainClass<>("");
}
}
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");
new MainClass<>("");
}
}
View Replies
View Related
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
2. xxx -> press 2 to choose this
So if they enter 3 or string or whatever i want to restart method and show again
1. xxx -> press 1 to choose this
2. xxx -> press 2 to choose this
So here is method that i am trying to restart
public static void askUser(){
System.out.println("xxx");
System.out.println("1. xxx");
System.out.println("2. xxx");
System.out.println("3. xxx");
[code]....
If i try to make it public void than it say can't call non-static methods inside static(main).if i try to put it into new class and then call it after i fail input it goes into infinite loop.
View Replies
View Related
