Implementation Of Stack Methods - Declaration Of Stack1 And Stack2
Jun 3, 2014
I have to implement all the stack methods in java such as push, pop empty, not using the ready methods but have to create them and to execute an exercise but is sth wrong with it
public class Stiva {
/** the problem is here how to declare the stack 1 and stack 2 and kreu(head) gjmax(size)*/
int Gjmax;
int array[] = new int[Gjmax];
int kreu;
private Stiva stiva1;
private Stiva stiva2;
I have to implement all the stack methods in java such as push, pop empty, not using the ready methods but have to create them and to execute an exercise but is sth wrong with it
public class Stiva { /** the problem is here how to declare the stack 1 and stack 2 and kreu(head) gjmax(size)*/ int Gjmax; int array[] = new int[Gjmax]; int kreu; private Stiva stiva1; private Stiva stiva2;
I have to implement all the stack methods in java such as push, pop empty, not using the ready methods but have to create them and to execute an exercise but something wrong with it....
public class Stiva { /** the problem is here how to declare the stack 1 and stack 2 and kreu(head) gjmax(size)*/ int Gjmax; int array[] = new int[Gjmax]; int kreu; private Stiva stiva1; private Stiva stiva2;
I have one interface with three(more than one) method declaration. In the subclass that implements it I want to define only one method not all three not even blank definition of them.Is there any keyword or method for that. How to do it? Is it possible to do it? In GUI we use adapter classes to achieve it. What for console application?
So I have this stack. I'm writing out all the operations and what not but I'm having trouble bypassing this "generic array creation" problem. I'm meant to be creating an array based implementation of a stack and from my research from google and my various attempts at things, I have not found a solution that works.
In addition; I have all the operations written that I need except for one final one. And that is clear(). clear() is meant to empty the array, essentially it is a popAll() method. Then all I need to do is set up so I can print out the arrays and I should be able to handle everything else.
StackInterface:
/** An interface for the ADT stack. */ public interface StackInterface<T> { /** Adds a new entry to the top of this stack. @param newEntry an object to be added to the stack */ public void push(T newEntry);
/** Removes and returns this stackÕs top entry. @return either the object at the top of the stack or, if the stack is empty before the operation, null */ public T pop();
Netbeans tells me it's an illegal start of expression during the initialisation of the interactWithUser method. public class InvertLetter {
/** * @param args the command line arguments */ public static void main(String[] args) { /** * String mit den Kleinbuchstaben. */ final String lowercase = "abcdefghijklmnopqrstuvwxyz";
Let's say within a class I create a method that takes care of creating a java swing layout with labels, buttons etc.. then attach an action listener (inner class) for each button to change a respective label text. All I would need is that the action listener method can access and modify the label as needed.
Have read about static, protected, private, getters and setters but honestly bit confused about which structure should be adopted as a best practice. Global static protected variables for the labels along with private inner classes implementing ActionListeners believe will do the trick and will be able to access the labels but not convinced this is good practice.
import java.util.HashSet; import java.util.ArrayList; public class Graph { double [] [] adj; graph (double [] [] a) { adj= new double [a.length][a.length]; for (int i=0;i<a.length;i++) for (int j=0;j<a.length;j++) adj[i][j]=a[i][j]; }
C:UserscDesktopGraph.java:: error: invalid method declaration; return type required graph (double [] [] a)
I'm new to Java and have been stuck on how to use a final declaration statement once it's made. Below is a class I'm creating with the intention of calling it under a main method. I don't understand if I'm supposed to do anything else, like do some sort of get/set, or if the final static line is all I need. And, I don't know how I call it to the main method once I do.
public class Shirt//class name. { int collarSize;//data field. int sleeveLength;//data field. public final static String MATERIAL = "cotton";//final data field for material.
I am not able to understand what does this URI exists at all ?? I feel it making things complex and meaningless or else i am missing something hidden and secret.
Whilst pre-preparing for java certification, one of the online mock exams has slightly confused me by saying my answer was incorrect for multi-dimension array 'declaration and instantiation'.
This is one of the answers i chose - which was marked as incorrect
a) int[][] array2d = {{123}, {4,5}};
Which looks absolutely fine to me.One of the other answers, which i agree is correct and so does the mock exam is
when a new object is created in Java it follows the idiom:
Object obj = new Object(); where the Object() constructor matches the object type Object.
But what if it doesn't? I understand from the Oracle Docs on creating objects and polymorphism that the constructor must be in that object's class or one of its subclasses. However, suppose we wanted to declare a new stack. My first instinct would be:
Stack s1 = new Stack(); But I assume it's valid to do it this way, too:
Object s2 = new Stack(); // Is there a difference here? What are we really saying about s2? I'm guessing s2 is simply an empty stack, but only has access to the Object class methods? I'm not sure why someone would ever do this, but I want to solidify my understanding of the Java hierarchy. Are there really any circumstances where someone would use a subclass's constructor when creating a new object?
What is exact difference between them? Another thing is when I check (a==b) it retuns me false, but when I check a.equals(b) it returns me with true. Why So?
I have an application that uses an object that is declared globally for the class. Within a method that is triggered by a user event, it creates a new object and assigns it to this global object declaration. My question is, when the object is overwritten multiple times by the user selecting the button that calls this method, will the older instances be garbage collected or is there still a reference to them? Is there any downfall to this logic and if so what would be a solution.
import java.util.Scanner; public class days { public EnumTest () { this.day = weeks/months/years} final int daysInMonth = 30; //constants final int monthsInYear = 12; final int daysInWeek = 7; public void convert()
[Code] ....
after compiling it shows invalid method declaration ; return type required.
1. In jsp 1 , i have 3 checkboxes(chkbox1,chkbox2,chkbox3) , if i select check boxes (chkbox1, chkbox2), and click on submit, corresponding two text fields (chkbox1,chkbox2) will have to appear in the next jsp i.e., jsp 2.
2. In jsp 1 , i have 3 checkboxes(chkbox1,chkbox2,chkbox3) , if i select check boxes (chkbox2, chkbox3), and click on submit, corresponding two text fields(chkbox2,chkbox3) will have to appear in the next jsp i.e., jsp 2.
Like this, which ever checkbox i select, corresponding text fields should appear in the subsequent jsp.
In the above program even if i comment out the Hashcode method , i believe it is still taking the memory address values from the native hashcode method of Object class. but the equals override implentation says that i have two insertions which are same . So as per my logic it should not allow the duplicate element to enter.but its not so ...the duplicate element is well inserted without hashcode .
How to implement GridLayout. In my applet, I want to make a grid of 2 rows and 2 columns. In each grid I want to add a Label and a TextField. I want the background to be red.
So my code would be?
import java.awt.*; import java.applet.*; import java.awt.event.*; public class GridLayoutApplet extends Applet implements ActionListener{ // construct components Label fNameLabel = new Label("First Name"); TextField fNameField = new TextField(20);
[Code] .....
I have read about panels and frames but, it is all confusing to me. How can you add a label and a TextField to one square of the grid?
Not necessarily Java related, more a general programming issue I have come a long and I am currently using java to mock up a project that will eventually get moved over to C++.
I am trying to implement FFT Convolution into a java project and have things partially working, I do not know if it is a coding issue, logic issue or if I simply know nothing of FFT and convolution.
For starters I got an FFT library that I do have working, if I create a small array pass it into the forward FFT, do a little bit of bit manipulation (converting a complex array of size n*2 into a re[] and im[] of size n), run the inverse FFT and do the same bit manipulation again I get back where I started.
However if I take two arrays, a Dirac Delta function (an array with a 1 followed by zeros for the rest of the array) and a stepping kernel (ex. {1, 2, 3, 4 etc}), I would expect to get the forward FFT of both arrays, bit manipulation, multiply them together, Inverse FFT, and bit manipulate again and the result would be the kernel. I have not had such luck.
This is the gist of the program:
// bit manipulation, converts complex array to two re and im arrays public void bitTwiddle(double [] real, double [] real2, double [] imaginary){
for (int idx = 0; idx < (N * 2); idx++){ realCopy[idx] = real [idx];
[Code] ....
This is the result:
Quote ===================================================================== Dirac Delta In Time Domain: Real:1.000.000.000.00 Imag:0.000.000.000.00 ===================================================================== Dirac Delta Frequency Domain Real:0.500.500.500.50 Imag:0.000.000.000.00 ===================================================================== Kernel In Time Domain Real:1.002.003.004.00 Imag:0.000.000.000.00 ===================================================================== Kernel In Frequency Domain Real:5.00-1.00-1.00-1.00 Imag:0.00-1.000.001.00 ===================================================================== Result: Dirac Delta x Kernel Real:2.50-0.50-0.50-0.50 Imag:0.00-0.000.000.00 ===================================================================== Result In Time Domain Real:0.501.501.501.50 Imag:0.000.000.00-0.00
Something about implementing Comparator interface isn't very clear to me: overriding the compare method.
Like here for example:
//This sorts a list of objects holding information based on age: the name and the age of the person
public class Person { String name; int age; public Person (String name, int age) { this.name = name; this.age = age;
[Code] ....
What exactly is happening behind the scenes? I don't understand mostly the part where it returns a 0, a 1, or a -1. After it returns one of those values, what really happens next?
For the displaying of the list, is the method toString() being accessed to output the list in the System.out.println statement?
