Driver Program That Creates 2 Instances Of A Class?
May 10, 2014
public class Car
{
//instance variables ----------------------
private String make;
private String model;
private int year;
private double vehiclePrice;
private double downPayment;
private double milesPerGallon;
[code]....
I created this class "Car" (also not sure if it's correct) and need to write a driver program that creates two instances of the class Car. One must use the default constructor, and the other must use the non-default constructor. It must demonstrate the methods used in the Car class using those instances.
public class DriverCar
{
public static void main(String[] args) {
Car car1 = new Car("Toyota", "Corolla", 2013, 20000, 3000, 35);
Car car2 = new Car("Ford", "Taurus", 2005, 14000, 1500, 25);
System.out.println(car1);
[Code] ....
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May 13, 2014
Assignment:
Create a class; call it Lab4a that will have one method called pull. This method does not return anything and requires no parameters.
-In the method, create three random integers in the range 1 to 7. The method will then display the three numbers to the terminal window.
-Now create a driver program, called SlotMachine, to invoke the pull method of the Lab4a class.
-As a refresher, you will have a main method in the driver class that will create an object of Lab4a and then use the only method of this object.
-In your driver program, invoke the roll method 10 times.
-See the back of this lab for an example of the output.
This is what I have so far.
Slot machine
import java.util.Random;
public class Lab4a {
public static void main (String[]args) {
Random pull=new Random();
[code]....
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Feb 12, 2015
I have a JPanel class that creates a left panel and a right panel. the left panel and right panel both have one button each. What I’m trying to accomplish is when I click on the button in the left panel that it updates the button in the right panel. I have to do this without changing anything in the right panel.Basically I have to have LeftPanel have a way to keep track of an instance of RightPanel and I would have to do this through the JPanel class. But I have no clue where to begin on even accomplishing this.
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Feb 19, 2015
Working on a program that creates an array from a file, organizes it in various ways, and then prints the results. Right now I'm specifically having trouble with the printAry() method - when I try to run it, I receive a NullPointerException for the active line in printAry() (EDIT: line 102). Not sure which sections are important to this, so I will include the client class and most of the service. I realize that the amount of documentation I included is not necessary, but it is required for the class.
class Lab3StudentAryService
{
private int count;
private Lab3StudentData [] studentAry = new Lab3StudentData[50];
/*
@param: none
@return: none
reads file and converts to array.
*/
public void fillAry() //constructor
{
Scanner scan = new Scanner(System.in);
[code]....
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May 2, 2014
Why we create a driver class?Instead of creating a driver class, if we want to compile our code so will it show output? Let say, we've created a class GradeBook of the institution for students.So they can easily view their profile information and scores in different semesters.so when we have created a class for this purpose, should we create a driver class or not?What is the big advantage of creating a driver class?
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May 2, 2015
I have a class named Base and a private variable named _hopcount i have 10 instances of class base i use _hopcount as creteria to some if but other instances edit _hopcount so i want to prevent _hopcount edit by other instances; I want to have private variable which other instances of same class can't modify it.
public class Base extends TypedAtomicActor {
private int _hopcount = 0;
if(_hopcount <= 3) {
some code;
}
public function() {
_hopCount += 1;
}
}
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Jan 9, 2014
What I have to do: Use Applet to create two instances of the Employee class. Display the data on the Graphics object. Display in the applet the names and values of all of the instance variables in each instance of the class. Also display the value of any static variables.
What I'm doing:
import java.applet.Applet;
import java.awt.*;
public class EmployeeApplet extends Applet {
public static int topSalary = 195000;
int hoursPerWeek;
public static void setTopSalary (int s) {
if (s > topSalary)
[Code]...
I'm not able to display hours per week for e1 and e2.
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Dec 11, 2014
I have to write a test class for a Contacts class called ContactTest and store the instances of Contacts created into a LinkedList.The ContactTest class should implement the addition andremoval of contacts to the Linked List and display its contents.
So far I have this, which stores the information entered into a Linked List, the problem is I don't know how I go about doing the addition and removal part.
Contacts Class
public class Contacts implements InterfaceContacts {
String fname;
String lname;
String phone;
String email;
//constructors
public Contacts( ){
this("****", "****", "****", "****");
[Code] ....
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Nov 1, 2014
How do I use two constructors and I'm having trouble with using char for gender...
Write a program to test the Person class defined below. Your test program should create two instances of the class (each to test a different constructor) and test each of the methods. You are also required to illustrate the error in trying to access private data members from the client class (for clarity temporarily change the private modifier to public and test again). See screenshots below for sample output.
The screen shots are displayed as:
p1 name = Not Given Age = 0 Gender = U
p2 name = Jane Doe Age = 0 Gender = F
p1 name = John Doe Age = 25 Gender = M
and
PersonTester.jave:20: name has private access in Person
System.out.println("p2 name = " + p2.name + "Age = " + p2.age + "Gender = " + p2.gender);
PersonTester.jave:20: age has private access in Person
System.out.println("p2 name = " + p2.name + "Age = " + p2.age + "Gender = " + p2.gender);
PersonTester.jave:20: gender has private access in Person
System.out.println("p2 name = " + p2.name + "Age = " + p2.age + "Gender = " + p2.gender);
3 errors
Here is the class given :
class Person {
// Data Members
private String name; // The name of this person
private int age; // The age of this person
private char gender; // The gender of this person
[Code] .....
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Feb 20, 2014
I am having trouble creating a driver for the following program. im new to creating interfaces and i need to make this work.
Lockable interface:
Java Code:
public interface Lockable {
boolean locked();
public void setKey(int key);
public void lock(int key);
public void unlock(int key);
} mh_sh_highlight_all('java');
[code]....
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May 14, 2015
I came across the below
1) When a variables are declared "Private" How should it be accessed from the driver class ? Sometimes i get an error in driver class saying "your variable is declared Private" why am I getting this error ...
The document says "Private" declared variables should be accessed only through methods. What does that mean.
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May 5, 2014
Okay, so I have to create a class with instance data and instance methods.
First, BankAccount class. It should contain the following information, stored in instance variables:
First name: The customer's first name.
Last name: The customer's last name
Balance: The amount of money the customer has in the account.
It should have the following methods:
BankAccount(String firstName, String lastName,
double openingBalance)
This constructor creates a new BankAccount
public String firstName()
Returns the customer's first name
public String lastName()
Returns the customer's last name
public double balance()
Returns the customer's account balance
Finally I need to create a driver to test my class. And create several accounts and verify that the first name, last name, and balance methods work properly. This is my code below.. I don't know if I did it right.
public class BankAccount {
String firstName, lastName;
double balance;
public BankAccount(String firstName, String lastName, double balance) {
[Code] .....
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Apr 13, 2015
I am to create a Array class then create a Driver class (TestArray) to test all the methods in the Array Class. Here's the code i've written for the Array Class. I just nee developing the TestArray class.
import java.util.Scanner;
public class Array
{
Scanner sc = new Scanner(System.in);
private double[] array = new double[];
public void setArray(double[] arr) {
[Code] ...
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Oct 30, 2014
I have a driver and a main program. How would I go along with calling the encode method to the driver class that I made so I can have the user inputs affected by the encode method?
Java Code:
public class ShiftEncoderDecoder
{
private int shift;
public ShiftEncoderDecoder(int shift)
{
setShift(shift);
}
public int getShift()
[Code] ....
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Jul 14, 2014
So I was going to try to create a program that prompts input and creates a file (That didn't exist before) with that input as name.Then, the program prompts inputs after stating questions such as 1 + 1, then if the user inputs an answer, put "Question # = Correct "or" Wrong.Code SO Far:
Java Code:
import java.io.BufferedReader;
import java.io.File;
import java.io.InputStreamReader;
public class File_Read {
public File_Read() {//File_Read is the Interactive object
[code]....
So that it puts the Correct or Wrong into the file.
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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) ?
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Jan 25, 2015
I want to make a method that takes a word and then checks if the word can be created from available letters. For example, if a word "johnson" can be created by using letters "jashoqwnon".
Now my goal is to make sure that if available letters contain a letter from the word, that letter is put into a String called result and then erased from the list of given letters. So, "johnson" and "jashoqwn" would produce the result "johns" and leave "aqw" unused.
Now the problem that I am facing is that I can't get Java not to use the same letter twice. So "johnson" and "jashoqwn" still gives "johnson".
I've tried everything in my power but I am missing something. Here is my code.
public static String makeAWord(String word, String letters){
String result = "";
for(int i = 0; i < word.length(); i++){
for(int j = 0; j < letters.length() ; j++){
[Code] ....
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May 4, 2014
I've written a die program, and i want the user to type any key in order to continue, how do i achieve this ?
I have already created a Die class, i just want to implement the main method now.
PHP Code:
package test;
/* This program demonstrates the use of a user-defined class
public class RollingDice {
// Creates two Die objects and rolls them display the values.
public static void main (String[] args) {
Die die1 = new Die();
System.out.println("Roll the die ")
}
} mh_sh_highlight_all('php');
What should i add after System.out.println, So that the user types (any key, or types "Enter" for example, for the die to roll). i dont want the die to roll by itself i Want the user to interact with the program in order for it to roll.
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Feb 11, 2015
So I want to write a constructor that creates a new object with the data from the array values. I don't know where to start. It's the last method in the code:
public class Measurements {
private double[] values;
private double[] newArray;
private int n; //numberofvalues
private double[] ms;
public Measurements(int max) { //constructor
[code]....
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Nov 3, 2014
The main Method
-Create a main method declares and creates an integer array called nums that can hold 15 integers.
-Use a for loop to fill that array with multiples of 3: 0, 3, 6, 9, etc.
-Then use similar for loop to print each value in the array on one line, with each value separated by a single space.
-Compile and run the program to see the result:0 3 6 9 12 15 18 21 24 27 30 33 36 39 42
As you write other methods, you'll also modify the main method to make calls to them. The printArray MethodWrite a method called printArray that accepts an integer array as a parameter. This method does not return a value, and must be declared as static so that the main method can call it. Instead of printing the array in the main method, move that loop into this method. Call the printArray method from the main method. Compile and run the program to verify it prints the sam result as before.Add a println statement so that after printing the array values on one line, it then moves to the following line.Finally, modify the loop in the printArray method so that, instead of using a traditional for loop, it instead uses a for-each loop. Compile and run the program again.
Part III: More Array Methods
The linearSearch Method In lecture we looked at a method that performed a binary search on a sorted array. A much simpler (though much less efficient) search is a linear search, that simply starts at the front of the array and looks at each element in turn until it finds it or reaches the end.Create a method called linearSearch that accepts an integer array and a single int value as parameters. The goal of the method is to find the second parameter (the target) in the array. The method should return a single int representing the index of the target value. This method should not print any output itself. In this method, use a traditional for loop to scan through the elements in the array. As soon as you find the target value, return the index of that value.
If you scan through the entire array without finding the target value, return a -1.Modify the main method to call the linearSearch method and print the results. Call it twice, searching for the value 18 (which it should find) and the value 10 (which it should not). Including the previous activity, the output of the main method should now look similar to this:0 3 6 9 12 15 18 21 24 27 30 33 36 39 42
The index of 18 is 6
The index of 10 is -1
The sumArray Method
The sumArray method should take an integer array as a parameter and return a single integer representing the sum of all values in that array.Use a for-each loop to access each value in the array and compute a running sum. After the loop, return the total.Call the method from the main method, producing the following augmented output:0 3 6 9 12 15 18 21 24 27 30 33 36 39 42
The index of 18 is 6
The index of 10 is -1
The sum of this array is 315
The addValue Method...The addValue method should accept an integer array and a single int as parameters. The purpose of the method is to add the second parameter to EACH value in the array. The addValue method does not return a value, but the elements inside the array will be modified. Call the addValue method from the main method, adding 100 to each element in the array. Then call the printArray method again to see the modified array values:0 3 6 9 12 15 18 21 24 27 30 33 36 39 42
The index of 18 is 6
The index of 10 is -1
The sum of this array is 315 100 103 106 109 112 115 118 121 124 127 130 133 136 139 142
Test a Different Array..Finally, duplicate the content of the main method to perform similar tests on another array. Instead of filling it with multiples of 3, fill it with multiples of 4. And instead of using an array size of 15, use an array size of 20.Modify the values search for to include one that is in the array and one that isn't.Rerun the main method and carefully check the results.If you haven't been doing it all along (which you should), make sure the appropriate class and method documentation is included.When you're satisfied that all methods are working correctly, modify the main method to delete the second array tests.
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Aug 16, 2014
I have the following program. In a nutshell, I creates an array of 3 consecutive ints and the user has to guess what those numbers are, knowing that they are between 0 and 7, this is from Head First Java. In the book, the code has a bug that is made on purpose and they challenge you to fix it. As you can see bellow, every time a user's guess matches a int in the array, the NumOfHits is increased by one. When the NumOfHits is 3 (the length of the array) the game finishes.
The bug is that if you guess 1 and 1 is in the array, if you type in 1, 3 times, I will increase the NumOfHits 3 times and end the game as if you had won. To solve the bug, you need to find a way to tell the program that if the user already guessed that number, it should no longer be taken into account and we shouldn't increase the NumOfHits if the same number is provided.
I "fixed" this by searching for the index of the number that matches an int of the array, and changing that index's value to 100, since the user knows that the numbers are between 0 and 7, they will not submit 100.
The result? If the user submits 2 and 2 is in the array, the value of its indexed is replaced by 100, so that if the user submits 2 again it doesn't count as a match.
Please see the comments in the code
import java.io.*;
import java.util.Arrays;
class DotCom{
int NumOfHits = 0;
int[] LocationCells;
public void setLocationCells(int[] locs){
LocationCells = locs;
[Code] .....
The code works, but for some reason, some times I get a ArrayIndexOutOfBoundsException run time error and it appears to be somehow random. This is what I saw on the command line earlier
C:Userspablo.alvarez>java launchDotCom
Enter a number: 3
missed
Enter a number: 4
hit
Enter a number: 5
hit
Enter a number: 7
missed
Enter a number: 5
missed
Enter a number: 4
missed
Enter a number: 3
missed
Enter a number: 4
missed
Enter a number: 5
missed
Enter a number: 6
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -1
at DotCom.checkYourSelf(launchDotCom.java:16)
at DotComGame.startGame(launchDotCom.java:59)
at launchDotCom.main(launchDotCom.java:72)
As you can see here, 3 returned 'missed' but 4 and 5 returned hit. Since the numbers are in sequence and are only 3, it makes sense that the last number is 6 (4,5,6). You will then notice that when I submitted 3 and 4 again it returned 'missed' as expected, because the numbers were already matched earlier, but then when I submitted 6, it returned the error seen above.
Sometimes this doesn't happen at all, sometimes it happens at the 2nd guess or third, it appears to be somehow random. I'm familiar with the error message, but I don't see where I'm using an index that doesn't exist in the array. The only time I'm referencing an array index is on
LocationCells[index] = 100;
but the index variable will only hold a value if the int submitted by the user matches on of the values in one of the indexes, so how is it that I'm going over the number of available indexes?
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Sep 29, 2014
a project I am working on. Its a program that creates a singly linked list that stores names and high scores and prints them. For some reason it is printing an entry extra times. Also my remove function is not working properly
GameEntry class:
package project;
public class GameEntry implements Comparable<GameEntry> {
private String name;
private int score;
public GameEntry(String n, int s) {
name = n;
[Code]...
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Apr 5, 2014
I need instantiating 3 instances of the RetailItem
//Instantiate 3 RetailItems
RetailItem jacket = new RetailItem(); ITS TELLING ME: constructor RetailItem in class RetailItem cannot be applied to given types
jacket= jacket.setDescription("Jacket"); <------- ITS TEllING ME: cannot find symbol
jacket = jacket.setUnitsOnHand(12);
jacket = jacket.setPrice(59.95);
[Code] ....
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Jun 17, 2014
Declaring the method as static precludes one from using any sort of object oriented programming, thus the method cannot access instance fields of the object if it needs to.
I created two short classes to sort of find out what this meant, but I feel I do not understand it well enough.
Test class (main):
package votek;
public class Test {
public static void main(String[] args) {
SomeMethod();
}
public static void SomeMethod() {
Character character = new Character();
character.totalLevel = 50;
System.out.println(character.totalLevel);
}
}
Character class:
package votek;
public class Character {
private int level = 0;
public Character() {
level = 50;
}
}
OR
Does it mean that making a static method in the class with private instances will prevent the method from using the private instances?
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May 22, 2015
I am learning JAVA and understanding some of its specific oddities. For example I notice that JAVA loves instances but not variables.
In Python:
x = 1
y = 2
print(x,y)
yields (1,2)
then I do y = x and print
getting (1,1)
This makes sense to me since x and y are variables and thats how variables work. In JAVA I notice this script:
public class TESTRUN {
public static void main(String[] args) {
int x = 0;
int y = x;
System.out.printf("x = %d, y = %d %n", x, y);
x = 9;
System.out.printf("x = %d, y = %d", x, y);
}
}
This yields:
x = 0, y = 0
x = 9, y = 0
So I get that JAVA doesn't understand variables? Or only takes instances of variables? Is there any way to yield a true variable or you always have to update variable relationships?
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Sep 10, 2014
"Write a program (save the program as ProductInventory.java) that will read data about 5 products from a text file (Products.txt. The program should use the data read from the file to create instances (objects) of Product.java(Use Product class as a Reference Type)."
I'm yet to discover how I will get the info from the textfile using scanners but I don't know how to "create instances of a reference type".
This is the code of Product.java that came with the exercise.
public class Product {
private String productCode = "";
private String productName = "";
private int quantity;
private String supplierName = "";
private String supplierAddress = "";
private double price;
[Code] .....
By the way, the exercise also required me to use the abstract class ProductLister. To be clearer, the text file is kinda like this:
54643
Rizer Mouse
Mark5s Merchandising
Marquee Mall
4
205.50
23412
Acer Ultrabook
JohnJade Merchandise
Cornal City
2
62200.00
93112
Dell Ultrabook
Octagon Marketing
Cornal City
3
68900.00
22126
Macbook Air Pro
Computerware Services
San Beda, Chad
2
93500.00
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