So I have 3 classes in this project, and When it compiles, I get a null pointer.
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.util.Scanner;
public class Project2 {
[Code] .....
Here's what I'm trying to do:
Complete the body of the following method. Use a CharQueue to store the input line as it is being read. The parameter is an EasyReader from Appendix B of the text. Use the method in.charInput( ) to read and return the next character of the EasyReader, and use in.isEOLN( ) to determine whether the next input character is the end-of-line.
public static int counter(EasyReader in)
// Precondition: There is a line of input waiting to be read from in.
// Postcondition: A line of input has been read from in, up to but not
// including the newline character. The return value of the method
// is the number of times that the LAST character of the line appeared
// somewhere in this line.
[EXAMPLE Input: ABBXDXXZX - The value returned by counter would be 4 for this input since there are 4 X's in the input line.]
***When I look at this I understand that I'm being asked to finish the method, that I have 1 input, which is an "EasyReader" object called in and that I use a CharQueue object along with the method isEOLN( ) to grab characters from in while looking for an end of line and then sticking the values in the queue and then I can go through the queue and figure out the number of times that last character shows up in the queue. I just am at a loss on the "how".
Suppose that a certain airport has one runway, that each airplane takes LandingTime minutes to land and TakeOffTime minutes to take off, and that on the average, TakeOffTime planes take off and LandingTime planes land each hour.
Assume that the planes arrive at random instants of time. (Delays make the assumption to randomness quite reasonable.) There are 2 types of queues: a queue of airplanes waiting to land and a queue of airplanes waiting go take off. Because it is more expensive to keep a plane airborne than to have one waiting on the ground, we assume that the airplanes in the landing queue have priority over those in the take off queue.
Write a program to simulate this airport's operation. You might assume a simulated clock that advances in one-minute intervals. For each minute, generate two random numbers: If the first in less than LandingTime /60, a "landing arrival" has occurred and is added to the landing queue, and if the second is less than TakeOffTime /60, a "takeoff arrival" has occurred and is added to the takeoff queue. Next, check whether the runway is free. If it is, first check whether the landing queue is nonempty, and if so, allow the first plane to land; otherwise, consider the takeoff queue. Have the program calculate the average queue length and the average time that an airplane spends in a queue. You might also investigate the effect of varying arrival and departure rates to simulate the prime and slack times of day, or what happens if the amount of time to land or takeoff is increased or decreased.
My Queue Interface: [URL] ....
My Queue Implementation: [URL] ....
My Demo (Main Method) Program: [URL] ....
Right now, I'm struggling with the demo program. I wrote some pseudocode in which I tried to match what the instructions were asking:
for(each minute) {
rand1 = generator.nextInt();
rand2 = generator.nextInt();
if(rand1 < LANDING_RATE / 60)
Add to the landing queue
if(rand2 < TAKE_OFF_RATE/60)
[Code] .....
Firstly, exactly how many minutes am I supposed to be doing this for? The assignment gave me a variable called final int ITERATIONS = 1440 , could that have something to do with how long I loop? Secondly, what exactly do I add to the queue if the conditions are true. For example, if rand1 < LANDING_RATE/60, what would I enqueue to the landingQueue? Thirdly, how am I supposed to check if the runway is free? Does that mean check to see whether the takeOffQueue is empty or not? Fourth, would allowing the first plane to land mean removing an item from the landingQueue? Also, what does it mean by "otherwise, consider the takeoff queue". Does that mean if the landingQueue is empty, I should start removing items from the takeOff queue?
The biggest problem is the fact that I have to calculate the average queue length and average time that an airplane spends in a queue.
i downloaded a sample database code of an online payroll system. How can i assemble it to know how it works.
the files include php and mysql files. it is to build an online payroll system
*Write a program to simulate this airport's operation. You might assume a simulated clock that advances in one-minute intervals. For each minute, generate two random numbers: If the first in less than LandingTime /60, a "landing arrival" has occurred and is added to the landing queue, and if the second is less than TakeOffTime /60, a "takeoff arrival" has occurred and is added to the takeoff queue*.
*Next, check whether the runway is free. If it is, first check whether the landing queue is nonempty, and if so, allow the first plane to land; otherwise, consider the takeoff queue. Have the program calculate the average queue length and the average time that an airplane spends in a queue.*
I have most of the code done as you can see below:
* Queue Interface: Queue.java
* Queue Implementation: ArrayQueue.java
* Demo Program: Airport.java
Right now, I am stuck on the first calculation which is trying to figure out the average size of the landing queue. For some reason, as you can see at the bottom of my demo program, the average always comes out to be 0.0 and I'm not sure what's wrong.
Secondly, how to calculate the average time a plane stays inside a queue for. Write a program to simulate this airport's operation. You might assume a simulated clock that advances in one-minute intervals. For each minute, generate two random numbers: If the first in less than LandingTime /60, a "landing arrival" has occurred and is added to the landing queue, and if the second is less than TakeOffTime /60, a "takeoff arrival" has occurred and is added to the takeoff queue.
Next, check whether the runway is free. If it is, first check whether the landing queue is nonempty, and if so, allow the first plane to land; otherwise, consider the takeoff queue. Have the program calculate the average queue length and the average time that an airplane spends in a queue.
I have most of the code done as you can see below:
* Queue Interface: Queue.java
* Queue Implementation: ArrayQueue.java
* Demo Program: Airport.java
Right now, I am stuck on the first calculation which is trying to figure out the average size of the landing queue. For some reason, as you can see at the bottom of my demo program, the average always comes out to be 0.0 and I'm not sure what's wrong.
Secondly, how to calculate the average time a plane stays inside a queue for.
My isEmpty method only returns false. Is something wrong? I printed the empty and not empty for testing purposes.
//determines if there are any items in the queue
public boolean isEmpty() {
if (front == -1 && rear == -1) {
System.out.println("empty");
return true;
} else {
System.out.println("not empty");
return false
}
}
I am trying to figure out stacks and queues and was trying to get this Palindrome program working so I could then play with it and use the Java visualizer site but for some reason the program isn't working correctly. It always states that the input is a palindrome no matter what the user input is.
The book that I got the code from is a little old so I changed a couple small things that I thought needed updating like adding scanner. I wanna use one with a custom array based stack and queue class rather than the java.util.Stack and Queue interface, just for understanding stacks and queues better hopefully.
import java.util.Scanner;
import javax.imageio.IIOException;
public class PalTest {
public static void main(String[]args) throws IIOException
{
Scanner scan = new Scanner(System.in);
PalindromeTesting x = new PalindromeTesting();
[Code] .....
I tried many times to return a string from java project to an android project But it keeps sending incorrect values as in 2 as it should be 1 here is an example.
Java Project:
boolean somethingboolean = false;
if(something.equals("1")){
somethingboolean = true;
}
public static String getString(){
if(somethingboolean == true){
[Code]...
Android project:
System.out.println(JavaProject.getString())
and in the android project it prints "FALSE"
So what should i do?
Implement a priority queue based on a sorted linked list. The remove operation on the priority queue should remove the item with the smallest key.
View Replies View RelatedI have a class "ExecuteJob" which has Print Q in the form of Priority Q.
You can keep adding job to the Q by calling one of the method in the class. However, and object cant do things simultaneity can it? While im adding a new job to the print queue, can it be executing and existing job in the print Q.
To achieve that, I would need to implement process and threads? I believe am I right? So that adding a job is independent to being removed?
I am in the process of implementing Priority queue, as I understand that there are many data structures you could use to implement. I implemented it with the an array, which it works absolutely fine. However I have limitations on what collections I can use from the collections classes. I fact I cant use any of the collections classes. Meaning I cant use array.
I’m trying to implement Priority Queue using heap. And implementing heap using binary trees. But however I have a few questions which I need to clarify and I cant think of any other way of resolving it. Ofcourse I can implement my own simple array class using linked list.
Inserting into heap would be quite simple, as I just need to find the right last position from left to right leaf to insert the node into the tree. However after inserting, you may want to make sure that leaf node values are > than root node. Therefore, the root node will always be with the highest priority.
I call these steps where you compare from top down as bubbledown and bubbleup. To do this I really need a for each node within the treee node to have attribute pointing to its root node. So in case of bubbleup I always have a pointer for a given node to its root, without it would mean I would to traverse through the entire tree to identify its root. Which I believe is very inefficient.
Or have I taken this completely wrong? Or is it the case that heap are only best with arrays and therefore use array (by implement it using linked list?)
I have a PriorityQueue called incoming, containing objects of type Vehicle.
All vehicles have a fuel level, that can be accessed by the getter method getFuelLevel().
I want to be able to choose to sort the queue so that the Vehicles with the lowest fuel levels are at the front of the queue.
I have an assignment to complete where I have to develop a Java Console application in Eclipse which accepts regional zone information for premises based upon addresses provided. The program needs to figure out which geographical zone each customer lives in and based upon their age, set a priority rating.
The zones (which is the Belfast and the directions) and sub-zones (which are the Postcode such as "BT1" are:
Zones
BELFAST
"BT1 ", "BT2 ", "BT3 ", "BT4 ", "BT5 ", "BT6 ", "BT7 ", "BT8 ", "BT9 ", "BT10", "BT11", "BT12", "BT13", "BT14", "BT15"
NORTH
"BT39", "BT40", "BT41", "BT42", "BT43", "BT44", "BT45", "BT46", "BT51", "BT52", "BT53", "BT54", "BT55", "BT56", "BT57"
SOUTH
"BT25", "BT26", "BT32", "BT35", "BT60", "BT61", "BT62", "BT63", "BT64", "BT65", "BT66", "BT67", "BT68", "BT69", "BT70", "BT71", "BT80"
EAST
"BT16", "BT17", "BT18", "BT19", "BT20", "BT21", "BT22", "BT23", "BT24", "BT27", "BT28", "BT29", "BT30", "BT31", "BT33", "BT34", "BT36", "BT37", "BT38"
WEST
"BT47", "BT48", "BT49", "BT74", "BT75", "BT76", "BT77", "BT78", "BT79", "BT81", "BT82", "BT92", "BT93", "BT94"
UNALLOCATED
No Postcode provided
What I specifically need to do is
1.Display a count of addresses within a user defined geographical zone.
2.Display all information for customers within a user defined geographical zone.
3.Display a complete set of captured data.
4.Display a prioritized list of customer details within each geographical zone.
5.Display a count of customers within each geographical zone.
Below is the code I have created so far for it.
package assignment1;
import java.io.BufferedReader;
import java.io.InputStreamReader;
public class Assignment1 {
private static InputStreamReader input = new InputStreamReader(System.in);
private static BufferedReader reader = new BufferedReader(input);
[Code] .....
The main issue I'm having is to make sure that data like address and customer counts, and customer details appear only for the selected areas.
I'm working on a lab for my class. I need to create a Priority Queue in Java using an array list. The kicker is that each node has to have a "handle" which is just an object which contains the index of of the node that it's associated with. I know that sounds weird but we have to implement it this way. Anyway, my priority queue seem to work fine except the handle values apparently aren't updating correctly because I fail the handle test. Also, I run into problems with handles only after extractMin() is called, so I figured the problem would be somewhere in that method but I've been through it a million times and it looks good to me.
Here is my Priority Queue Class:
package lab3;
import java.util.ArrayList;
/**
* A priority queue class supporting operations needed for
* Dijkstra's algorithm.
*/
class PriorityQueue<T> {
final static int INF = 1000000000;
ArrayList<PQNode<T>> queue;
[Code] ....
I can post the tests too but I don't know if that would do much good. Just know that the queue works as is should, but the handles don't point to the right nodes after extractMin() is utilized.
So we have to ask the user to put in a string of letters, and bring those letters in as cars to where there is a storage area and an assembly area, and we have to sort them from there into the assembly area with the smallest (A) at the head. I think I set up my code pretty well, but when I run it, no matter what I put in it returns CBAo. Say I input KATE, it should return TKEA but instead CBAo or if I input JANICE it should return NJIECA but it just returns EDCBAo. Here's my code:
import java.util.Scanner;
import java.util.Stack;
public class carStacksDessart
{
public static void main(String[] args) {
Stack<Integer> storage = new Stack();
[Code] ....
My assignment was to create a priority queue for Airline Passengers. Here is what I have done so far:
//Driver
package priorityqueuestandby;
import java.util.NoSuchElementException;
import javax.swing.JOptionPane;
public class PriorityQueueStandBy {
public static void main(String[] args) {
[Code] .....
So the part that I cant figure out is:
When a standby passenger is to be enqueued into the priority queue, it must be done so that at the moment of each dequeue operation, the item at the head of the queue is the standby passenger with the longest longevity, and also so that passengers with the same longevity are dequeued in a first-come-first-served fashion.
he says that we need to "Make your program so that it extends Comparable and implements the compareTo() method properly..."
So I was looking at the Comparable class and I could't find a compareTo() method... I am not confident I know how extends works either. I am assuming I need a new class if I am going to be extending another class. Right now I am taking in longevity as a String and converting it to an int because my last ditch effort is going to be to set up a loop that will organize longevity into a/an circular array based on the size of the incoming integer.
write a code using the stacks?i want the output to produce my name.
View Replies View RelatedI am having some trouble with this program. I am getting only one result to print when it should show all the solutions. Also the 1 solution I am getting is only printing 7 queens not 8.
import java.util.Stack;
public class Queen1 {
boolean conflict, complete = false;
public int solve(int n) {
//create a stack
//each element stores the position of the queen on a different row
Stack<Integer> s = new Stack<Integer> ();
[Code] ......
I got to make a java code for my class. I must make a calculator using stacks. I have a code but i got some mistakes. Here is the code
Java Code:
package stackscalc;
import java.util.Scanner;
import java.util.Stack;
import java.util.EmptyStackException;
class Arithmetic {
int length;
Stack stk;
String exp,
[Code] .....
i got a problem with this program.I am supposed to make a calculator using stacks but it seems that i m stack. i can t get the right recognition
for () and {} []
its not necessary to use all these symbols.just a simple () will do .here s the program
package stackscalc;
import java.util.Scanner;
import java.util.Stack;
import java.util.EmptyStackException;
class Arithmetic
{
int length;
Stack stk;
String exp,
postfix;
[code]....
public class ThreeStackArray
{
static int row = 10;
static int col = 2;
int[][] stack = new int[row][col];
//place numbers into the first row of array
public void push(int num)
[Code] .....
I found this program idea online. Make a array with three stacks. Either I jump out of bounds if I use "continue" instead of "break" in my loop in the push method. If I use break the output looks like:
12900
0000
0000
0000
0000
if I use continue the output looks like:
An error has occured java.lang.ArrayIndexOutOfBoundsException: 2
1212
1212
1212
1212
1210
I am trying to write a program that checks for parentheses matching using stacks.This is my ArrayStack class.
public class ArrayStack{
private final int DEFAULT_SIZE=10;
public int tos;
Object[] array;
public ArrayStack(){
array=new Object[DEFAULT_SIZE];
[Code] ....
But the problem is when I compile matching I get an error as unreported exception EmptyStackException.must be caught or declared to be thrown. I think the problem is with exceptions which I don't have a good knowledge of.
I'm supposed to use stacks (implemented with an array) to check to see if a string is a palindrome. I've finished all my classes and methods, but I'm getting an ArrayIndexOutOfBoundsException when I try to run my demo program.Here are my classes:
public interface Stack {
// Creates an empty stack
public void initializeStack()
// Returns true if the stack is empty, returns false otherwise
public boolean isEmpty();
// The stack can never be full, so always return false
public boolean isFullStack();
[code]...
I'm getting errors on all the exceptions called EmptyCollectionException. I think this is because the import statement has a error on it but I'm not sure. I'm suppose to add methods for peek, isEmpty, size, and toString methods. I only started isEmpty also am wondering what I have to change from peek method if anything at all.
import jsjf.exceptions.*;//Error on jsjf
import java.util.Arrays;
public class ArrayStack<T> implements StackADT <T> { //Error on StackADT
private final static int DEFAULT_CAPACITY = 100;
private int top;
private T[] stack;
[Code] .....
I am doing a calculator using stacks but when i try to calculate I getting the wrong data example stack contains 8 and user enter -3 stack should change to 5.
package comp10152.lab5;
import java.util.Scanner;
import java.util.Stack;
[Code].....
I was given some code by a professor to add some features to as part of an assignment. However, the code itself doesn't seem to work.
import java.util.HashSet;
import java.util.InputMismatchException;
import java.util.PriorityQueue;
import java.util.Scanner;
import java.util.Set;
public class DijkstraPriorityQueue
[Code] ....
The method to find minimum distance is nonfunctional...I receive an error that the types are incompatible. I can't do the assignment if the base code doesn't work to begin with...