I have to make an applet that uses an array to list 5 songs and the applet has to scroll the list of song titles, one at a time, each song title should start at the top of the applet and scroll to the middle then, scroll off the right hand side, each new song title should scroll in a different color, the applet should loop, when it gets to the end of the list, start over again at the beginning of the list. the code compiles fine put when I go to run the applet nothing shows up in it and a wall of text appears in the command prompt.
I am creating a hangman game and I want to read in a list of words from a text file, but after the user inputs the name of the text file. I get 'Exception in thread "main" java.lang.NullPointerException'.
Here is the code, where I think the problems lie.
public void runModel(){ ArrayList<String> pirateWordsList = new ArrayList<String>(); System.out.println("What is the name of the file you would like to load? (The file included is called piratewords.txt'"); Scanner in=new Scanner(System.in); String file=in.next(); load(file);
[Code] ....
The full error message is this:
Exception in thread "main" java.lang.NullPointerException at uk.ac.aber.dcs.pirate_hangman.Model.load(Model.jav a:108) at uk.ac.aber.dcs.pirate_hangman.Model.runModel(Model .java:45) at uk.ac.aber.dcs.pirate_hangman.Main.main(Main.java: 6)
Im trying to create a program in which I read line by line the contents of a text file, and then report each letter along with its frequency. I was wondering how to read through the lines and process it so that my program knows to increase by a number each time a letter appears in my text file. For example, if A appears in my file 5 times, B 3 times, and C 0 times I want to eventually print out
A -- 5 B-- 3 C-- 0
My first thought was to do this using array lists but is there any way I could do this without using one?
method called []getLetterGrades but the only hint My professor told me was that I needed to declare another array list for this method and he wouldnt tell me anything else so bummer. But I don't understand why if what we are returning is a char. It would make sense to return an array list of char to get letter grade. Which is what i did but since the function is a char, the array list character wont work as a return.Primarily i would like to know the type that is needed. I just want an explanation for an array list in this method and how it would serve in this method.
Directions: public static void initialize(ArrayList names, ArrayList sores)
You should write a function that sorts both array lists, based on the values in the scores array list. This is one of the more conceptually challenging parts of the assignment. You want to sort the scores array list, and simultaneously alter the names array list so that the names continue to line up with their respective scores by index. In the example data above, when the score 9900 moves to the first element of the scores array list, the name "Kim" should also be moved to the top of the names array list. The function should have the following signature:
I'm having trouble figuring out how to sort the lists.
import java.util.ArrayList; import java.util.Scanner; public class Assignment5 { /** */ public static void main(String[]args) { intializeArrays();
I had to write a program that prompts the cashier to enter all prices and names, adds them to two arrays lists, calls the method that I implemented, and displays the result and use 0 as the sentinel value. I am having difficulty coming up with a for loop in the method, I believe I have the condition right but I am having trouble with the statements. I now know that String does not have the get property, but I have only done examples with integers and I am not very good with for loops and wouldn't know how to fix it.
public static void main(String[] args) { Scanner in = new Scanner(System.in); ArrayList<Double> sales = new ArrayList<Double>(); ArrayList<String> names = new ArrayList<String>(); System.out.print("Enter Number of Customers"); double salesAmount; System.out.print("Enter Sales for First Customers"); salesAmount = in.nextDouble(); while(salesAmount != 0)
I am stuck on this exercise and I don't know what exactly is wrong. I think it's something with the .remove and the for each loop, but I am not sure.
public class seven { public static void main(String[] args) { ArrayList<String> list = new ArrayList<String>(); list.add("aaa"); list.add("brr"); list.add("unni");
[Code] ....
This is what i get
Exception in thread "main" java.util.ConcurrentModificationException at java.util.ArrayList$Itr.checkForComodification(Unknown Source) at java.util.ArrayList$Itr.next(Unknown Source) at seven.removeDuplicates(seven.java:24) at seven.main(seven.java:18)
private int coin; Money(int c) { coin = c; } int showCoin() { return coin; }
and for a test class, I need an array list with a couple of coins in it (i.e. ONE_POUND, TWO_POUNDS) and a loop that adds together the values of the coins in the list and prints the result. How can I do this?
I have this very simple application just to test console input:
import java.util.ArrayList; import java.util.Scanner; public class WriteTester {
[Code]....
When I let it run, only every third entry is put into the array list and I have to hit "enter" three times for the "break" in line 21 to trigger. I cannot find out why.
Im making a simple code to add an array to a List (the code im referring to is <String> )
import java.util.*; public class L5_ArrayListProgram { public static void main(String[] args){ String[] things = {"lasers","ghouls", "food", "dark"}; List<String>list1 = new ArrayList<String>(); for(String x: things) list1.add(x);
My simple question is - what are the <String> ...<String> for? I understand it makes the list1 variable a string, but why is it made like this? do we usualy use <String> when we need to make a variable a String?
My assignment is to create an array list and compare the total salary of two salespeople. I'm wondering if I can use JOptionPane to select an existing sales person from the list and print their information.
I am not having any trouble with the calculations and comparisons, but I am finding limited resources on "searching" for a specific person with JOptionPane.
Here's what I have so far.
public class SalesPeople { String personName; double annualSalary; double salesAmount; double percentComission; public SalesPeople(String xPersonName, double xAnnualSalary, double xSalesAmount, double xPercentComission) {
An array which contain a list of names. I let for a user input and I use that to search through the array. For example lets say the string name "Christian" is stored inside the names array and the user types in Chri, the program looks in the array and finds a name that contains Chri and prints them out. How do I go about doing this?
The program is where you will click anywhere in the jframe and it will draw a new rectangle. I have altered the code given to us but the problem that I am having is the fact that when I click the rectangle will always be connected to the upper left hand part of the jframe, no matter where I click. The program should create rectangles of the same length and width wherever you click. Here is what I have. I believe I have to change something in the addRectangle method, but nothing that I have tried works.
Java Code:
import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.Rectangle; import javax.swing.JComponent; import java.util.ArrayList; public class RectangleComponent2 extends JComponent
Suppose that you have an ArrayList and that it contains String objects. Which declaration of the ArrayList requires that objects retrieved using the get method be cast to Strings before calling a String method?
I. ArrayList a = new ArrayList(); II. ArrayList<Object> a = new ArrayList<Object>; III. ArrayList<String> a = new ArrayList<String>;
A. I only B. II only C. III only D. I and II only E. I, II, and III
I know that all of these are ways to declare an Array List, but I am unfamiliar with the last two since I usually just declare my Array Lists with the first option.
In my project I need to create a pizza ordering system. I have created a array list of pizza toppings and each pizza topping must have a cost property associated with it, then the user can pick the toppings they want and the cost of each topping will be added up and the total cost of the whole pizza will be displayed. But I don't know how to associate a cost with each topping. I have been told that I can access the cost through a get/set method and store it in a private member variable. But I don't know how to do this?
I've tried to do it, but it hasn't worked. This is the code
If you see in the code below where I print "Would you like to use previous key" I need to be able to save the previous key answers to be used again.. not sure how to go about doing this..
import java.util.Scanner; public class Main { public static void main(String[] args) { String[] studentName = new String[20]; int[] studentAverage = new int[20]; Scanner input = new Scanner(System.in);
I am having a hard time trying to figure out how to print random numbers from a an array list. I tried google but nothing worked. I have to pick certain values from two lists and print them on the screen. I have included comments in the code to facilitate the explanation.
import java.util.Random; public class Parachute { public static void main(String[] args) { Random randomNumbers=new Random(); int number; int array []={1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21}; char A[] = {'a', 'b', 'c','d','e','f','g','h', 'i','j','k','l','m','n','o','p','q'};
