Count Number Of Books In Arraylist?
Jan 29, 2015
We have been given an assignment to create a small library, with the following classes Library, Book, Author and Copy. With a given class Biblio which has predefined code and adds the books to the class book in an arraylist in Class Copy.
The UML Domain is attached so you know the flow of the classes Everything is working fine and the generated output is correct.
There is just one method in class Library that is not working, the int method has to count the number of Copy's based on the Class Book (String):
I have to go through the Arraylist in Class Copy and look for a specific book and return the number of copy's.
I have tried multiple steps using a for loop Now I have found a similar post the uses hashset, I have tried below code but the return comes back with 0. (There are 3 copy's)
package domein;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
import domein.Boek;
import domein.Exemplaar;
[code]....
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May 19, 2014
//read the file
//make the numbers 1 string line
//count the number of repetitiveness in the string for the numbers
//display four lowest ones
import java.io.*;
import java.util.*;
public class Lottery2
[Code] ....
when I run it the array gets sorted but how do i keep the data in other words
what it is supposed to do is grab numbers from a file, and give me the lowest 4 numbers back. I know the numbers using the array but how do i pull out the lowest 4 and keep the data true no matter what numbers or how many of them are in the file.
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May 14, 2015
I'm trying to count the number of elements in an ArrayList which also have duplicates. So for example, in an ArrayList of strings which contains cat, cat, dog, horse, zebra, zebra, the answer should be two.
If an element is found to be a duplicate, that element should then be exempt from the search so if that element is found again it should not increase the duplicate count.
Here is my code:
public int countDuplicates() {
int duplicates = 0;
// TODO: Write the code to get the number of duplicates in the list
for (int i = 0; i < list.size()-1;i++) {
boolean found = false;
[Code] ....
I know it's wrong because right now it's still increasing the duplicate count for elements that have already been detected as duplicates. How can I make it stop doing this?
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Sep 11, 2014
What I'm trying to do here is to count the vowels in an arraylist of strings. What I did may not be right, but that's not my problem for now. My problem is that i cannot return the value (n) I want to return. I don't know why.
import java.util.*;
import java.util.Arrays;
public class One {
public static void main(String[] args) {
ArrayList<String> list = new ArrayList<String>();
list.add("aaa");
list.add("brr");
list.add("unn");
System.out.println(vowels(list));
[URL] ....
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Mar 24, 2014
So I have 2 args[] one that reads the file name in the same directory and the other that tries to count how many of any letter (maybe even words) in the txt file ....
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Mar 28, 2014
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
public class Paragraph {
public static void main(String[] args) throws FileNotFoundException, IOException
[Code] .....
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Jul 20, 2010
i want to create a program in java which counts the number of prints taken from a printer..
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Feb 4, 2015
I am using count++ in my program in order to count the number of division that occurs. It works but outputs:
The number of divisions is 1
The number of divisions is 2
The number of divisions is 3
The number of divisions is 4
The number of divisions is 5
All i want is the last line. How do I solve this?
import java.util.Scanner;
public class Program3
{
public static void main(String [] args)
{
int div;
[Code] ....
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Jul 21, 2014
Given a Numbers instance, whose fields are arrays of all the built-in Java numeric types (int, long, float, double, big-decimal, etc), write a method to sort all the numbers into a master list, and then print out the numbers where the number of digits past the decimal point is equal to the index of the number in the master list.
Is there a function in Java that will give me just the numbers after the decimal? I tried Decimalformat but couldn't get it to work. Here is what I have so far; however, I think I might be on the wrong track.
public class Numbers
{
public static void main(String[] args) {
Byte bNum = new Byte((byte) -50);
Integer iNum = new Integer(168);
Long lNum = new Long(100000L);
Short sNum = new Short((short) 10000);
Float fNum = new Float(12.19f);
Double dNum = new Double(23.123);
BigDecimal bd = new BigDecimal("3.14159265358979323846");
[code]....
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Jan 19, 2015
So far so good, I need to count the number of rows in a table. What I wrote:
<sql:query dataSource="${statistics}" var="result4">
SELECT COUNT(id) AS count FROM statistics;
</sql:query>
<c:forEach var="row" items="${result4.rows}">
Total players: ${result4.count}
</c:forEach>
But, it doesn't work.
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Dec 14, 2014
I'm trying to write a program that counts the number of times each number in an array occurs. In theory I understand how it work, you take the first element in the array, compare it again the rest of the array and any time it occurs in the array you increment a counter by 1. Then move onto the next element A[1] and so on...
This is what I've done so far :
public static void main(String[] args) {
int[] array = {5,6,2,5,2,2,0,1,6};
int count = 0;
for(int i = 0; i <array.length; i++) {
int val = array[i];
for(int j = i+1; j<array.length; j++)
[Code] .....
I think I'm on the right track as it correctly prints out the frequency of the first 3 elements, but I'm definitely going wrong somewhere as it just doesn't do it right after that!
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Aug 30, 2010
In our web application we are using servlets,jsp and spring technologies.Here we are also maintaining session mechanism in our application.But now i need to count number of users accessing our web application at a time. How can i implement this mechanism...
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Apr 6, 2015
I am trying to count the number of occurrences of a string in an array list. I used the following code:
int count = Collections.frequency(strings, search);
strings is the name of the array list and search is the string that I am trying to count the number of occurrences of. My program compiles correctly, but when I enter the string to search for, I get the following error: "Exception in thread "main" java.lang.NullPointerException at java.util.Collections.frquency(Collections.java:37 18)
Why am I getting this error message and how do I fix it?
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May 24, 2014
I need to read the contents of file A, and B and store it in file C by joining the contents of A and B and also counting the number of letters/characters present in it.
I've come up with this so far.
import java.io.FileInputstream;
import java.io.FileNotFoundException;
import java.io.IOException;
public class JavaApplication43{
public static putwrite(string fname) throws FileNotFoundException, IOException
[code]...
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Nov 16, 2014
I have problems getting the right number of times for each number of the array. Here is my code:
public static void main(String[] args) {
int[] a = { 3, 13, 5, 9, 13, 6, 9, 13, 2, 3 };
int num = 3;
int count = numbers(a, num);
for (int i = 0; i < a.length; i++) {
[Code]...
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May 2, 2014
I have been working on this for hours and cannot get it to work properly. The program is to count the number of characters contained in both strings and display the results. It is also to display the final statement, but only once. This version has a complete statement for each matching character.
import java.util.Scanner;
public class CountMatches {
public static void main(String[] args) {
String firstStr = ("");
String s1 = firstStr;
[Code] ....
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Oct 15, 2014
I'm attempting to create a program that employs a method to count the number of 7s a user puts as an input into the program. I'm just getting started, but I'm getting an error when I try to implement a main method that says "Illegal start of expression"
What adjustments could I make to eliminate this error message?
// Add a main method here.
public static void main(String[] args) {
//Error occurs here
public static int countSevens(int n) {
// 0. Clean-up. Get rid of any minus signs as that is not a digit.
n = Math.abs(n);
[Code] .....
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Mar 7, 2014
Write a program using a while-loop (and a for-loop) that asks the user to enter a string, and then asks the user to enter a character. The program should count and display the number of times that the specified character appears in the string. (So, you will have two separate program codes, one using a while-loop and the other one using a for-loop.)
Example:
Enter a string: "Hello, JAVA is my favorite programming language."
Enter a character: e
The number of times the specified character appears in the string: 3
I don't even know where to begin I've only got this
import java.util.Scanner;
public class letterCounter {
public static void main(String [] args) {
Scanner sc = new Scanner(System.in);
System.out.println("Enter a string");
String myString = sc.nextLine();
System.out.println("Enter a letter");
String letter = sc.nextLine();
}
}
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Jan 22, 2015
IDE: BlueJ
I'm creating a small program to count the number of mouse clicks the user is inputting into a BlankArea for a school assignment. I just finished with making the program look nice and all so I was putting in a MouseListener to detect the clicks. However, when I tried adding a MouseListener to the code, the error in the title appeared.
Java Code:
import javax.swing.*;
import java.awt.*;
import javax.swing.border.*;
import java.awt.event.*;
public class CountClick
{
JTextArea textArea = new JTextArea();
[Code] ....
Here's what's going on:
Compiling causes error as described in Title Java Code: createAndShowGUI() mh_sh_highlight_all('java');
cannot be referenced from a static context appears Java Code: public static void main(String [] args) mh_sh_highlight_all('java');
It contains the thread safe and program previously launched without mouse functionality(program appeared when there were no MouseListener components and thread safe had all static method stuff).
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Mar 26, 2014
I am trying to flip a coin 1000 times and make the driver class count the number of times a head and tails appear. However, I am having some trouble trying to figure out the error:
package Week5;
import java.util.Random;
public class Coin {
private int heads;
private int tails;
private int face;
[Code] ....
I was able to print out the generated numbers, but java will print either heads or tails a thousand times and count that as 1000 and nil for the other probability...
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Jan 30, 2014
I am trying to restrict the number of views in JSF 2.0.2 using
<context-param>
<param-name>org.apache.myfaces.NUMBER_OF_VIEWS_IN_SESSION</param-name>
<param-value>5</param-value>
</context-param>
In my case my managed bean is View Scoped and it supports a UI page which has multiple forms and each form is submitted as AJAX POST request.
As per the statndard, setting restriction to 5 should create 5 views and after that based on LRU algorithm the oldest views should get deleted if 6th views is created.
Therefore any action on the oldest view will throw the ViewExpiredException and i simply redirect the user to view expired page.
1) When i set the restriction to 5 views, i open 4 tabs with 3 forms each.
2) I submit the 3 forms on first tab everything works fine.
3) As soon as I go to 2nd tab and submit the first form thr, i get view expired exception
4) It seems I am exceeding the number of views I mentioned in web.xml
I want to know :
1) Does every AJAX POST submit itself creates a view ?
2) How I can count the number of views created in a session ?
3)Can i force expiry of a view in JSF 2.0.2 while the session is still alive ?
4) Normally JSF 2.0.2 session cachces the views. Lets assume session is alive the entire day but a view was created in morning at 9:00 AM and is not used again the entire day. Assuming that session doesn't reaches the max number of views it can save in entire day, will the view created in morning expire on its own after certain interval of time ? If not , can we still force its expiry while keeping the session alive ?
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Jun 19, 2014
I have a calculation that sorts books by rating...
System.out.println("
" + "
Sorted by Rating
");
for (int count = 0; count < bookL.size(); count++) {
for (int in = 0; in < bookList.size() - 1; in++)
if (videoList.get(in).getRating() < bookList.get(in + 1).getRating()) {
[Code] ....
What am I missing here? Why doesn't this work?
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Oct 9, 2014
import java.util.Scanner;
public class LM6Assignment
{
public static void main(String[] args)
{
Scanner inputDevice = new Scanner(System.in);
int numBooks = 0;
double onePhotoBook = 10.99;//each book cost 10.99
double costof1Book;
//mehtod calls
costof1Book = computeBill(onePhotoBook);
[Code] ....
How to code it so I can put in how many books they need and for it to show up with the amount for multiple photo books..
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Jul 8, 2014
I was trying to come up with the design for a library. Here are the requirements:
The library maintains a record of books and its members. It allows members to check out books. Books can be searched by author name or title. The books are classified into 4 categories - General, Sports, Politics, Business.
I've come up with this initial design:
Classes:
Category (enum)BookMemberLibrary
Category
Attributes: SPORTS, GENERAL, POLITICS, BUSINESS
Book
Attributes: String title, String authorName, Category category, boolean checkedOut
[Code] .....
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Jun 30, 2014
I have an array with the following characters {'E', 'L','E','P','H','A','N','T','P','O'}
now, I need an array that will store the first array such that only the occurence occurs e.g {'E','L','P','H','A','N','T','O'} Notice that the characters 'E' and 'P' occur twice and as a result were not repeated the second time in the new array.
How would one go about this using the counting elements technique?
I tried this but not sure how to use the counting elements technique.
char [] arr = new char{'E', 'L','E','P','H','A','N','T','P','O'};
char[] bucket = new char[(arr[0] * arr.length)];
for (int i = 0; i < len; i++)
bucket[arr[i]]++;
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Mar 24, 2014
I need to create a program that uses ArrayList to store integers the user inputs, then scan the array for the largest number. I would also like the user to be able to exit this loop if the number 0 is entered.
As you can see below, I'm not sure how to correctly exit the do-while loop. I found this on another forum, but it does not work.
Java Code:
import java.util.*;
public class array {
public static void main(String [] args){
ArrayList<Integer> list = new ArrayList<Integer>();
[Code] ....
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