Why Not Getting All The Elements In TreeSet
Aug 1, 2014
public void createPersons() {
Random rand = new Random();
for(int index = 0; index < persons.length; index++) {
Person person = new Person(rand.nextInt(maxAge), persons[index]);
setOfPersons.add(person);
[Code] ....
setOfPersons is a TreeSet, persons[] is an array of strings that contains 10 names. Why printPersons() prints only the half names of setOfPersons?
Note. I do get the size of the TreeSet as 10...
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Aug 2, 2014
public class Person implements Comparable<Person> {
// the age of the person
private int age;
//the name of the person
private String name;
//the Integer object to wrap the age value;
private Integer ageWrap;
[Code] .....
The collection library has a class named TreeSet, which is an example of a sorted set. Elements in this set are kept in order. Carefully read the description of this class, and then write a class Person that can be inserted into a TreeSet, which will then sort the Person objects by age.
This is the exercise I am trying to solve. And this is as far as I have gotten to. Is it possible to sort my setOfPersons TreeSet directly? I tried to use
Collections.sort(setOfPersons)
method but it wont compile, and I realized that it is not applicable to TreeSet. So I made the
sortByAge()
method to do it indirectly...
I am puzzled though because in the exercise it states
write a class Person that can be inserted into a TreeSet, which will then sort the Person objects by age.
meaning that the TreeSet will sort the Person Objects and not my class..
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Mar 12, 2014
What is the difference between HashSet, TreeSet and LinkedHashSet?.One difference between HashSet and TreeSet is that TreeSet is sorted, whereas HashSet is not sorted. I dont know the other differences
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Nov 23, 2014
I am using a TreeSet to tokenize a string. The output is sorted with numeric first followed by words
E.g. 13 26 45 and before etc.....................
Is there a tidy way to remove the numeric?
Last bit of my code is :-
// print the words separating them with a space
for(String word : words) {
System.out.print(word + " ");
}
} catch (FileNotFoundException fnfe) {
System.err.println("Cannot read the input file - pass a valid file name");
}
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Feb 5, 2015
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class array
{
public static void main(String[] args)
[Code] ...
Is there a way to write this, where, alpha is one array.
Write a program that declares an array "alpha" of 50 elements of type "double". Initialize the array so that the first 25 elements are equal to the square of the index variable and the last 25 elements are equal to three times the index variable. Output the array so that 10 elements per line are printed.
If I have an array of 50 integers, can I break that to read in lines of 10?
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Jan 12, 2015
I am trying to make a 2d array that keeps track of comparison counts. what I have so far works ok but writes over the previous elements with 0. can't seem to find where I am re-initializing the previous elements.
//this is one of my fill sort arrays
public void fillSelectionArray(int index, long countSum) {
//rand = new Random( );
//for ( int i = 0; i < listsize; i++) {
selectionList[ index -1] = countSum;
// }
[Code] ....
I know I am missing something just not sure what.
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Mar 13, 2015
I have a requirement to add elements to a map. But for, First iteration it inserts fine and for next iteration elements are overrided.
I am just wondering if there were append() in map or in any collections?
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May 4, 2015
What is the sum of the array ar elements after executing the following code?
int[] ar = {1,2,3,4,5};
for (int i=0; i<ar.length-1; i++)
if (i%2==0) ar[i]=i;
My professor says the answer is 12 i dont know how he got that answer
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May 17, 2014
I cant get this code to work if wont find the right min and range and its printing out my max three times . This is what I got
public static void main(String[] args)
{
double [] Rainfall = new double[12];
Rainfall[0] = 77.4;
Rainfall[1] = 56;
Rainfall[2] = 61.8;
Rainfall[3] = 62.1;
Rainfall[4] = 57.1;
[Code] ....
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Mar 29, 2015
I have two arrays
private ReservedBook[] reservedBooks;
private LibrarySystem[] libraryBooks;
The library array has two books and I want to copy one of them to the reserved books when you type in the ISBN
public void borrowBook(String ISBN)
{
int i = 0;
if(numberOfBooks < MAX_BOOKS-1)
{
if(libraryBooks[i].getBookISBN().equals(ISBN))
{
for(i=0;i<MAX_BOOKS-1;i++)
reservedBooks[i] = libraryBooks[i];
}
else System.out.println("There is no such book");
}
else System.out.println("You have reached the maximum number of allowed books");
}
It shows me error: incompatible types - LibrarySystem cannot be converted into ReservedBook. How can I fix it?
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Aug 24, 2014
Referring Code 1, the book says line 16 of the code removes the element "Three" but line 17 does not remove the element "Four" because of Statement 1. The question is does remove(Object o) method invoke the == or the equals method because statement 1 and 2 seem to be in conflict
Statement 1:
Two objects are equal if their object references point to the same object. (which is nothing but definition of ==)
Statement 2:
The author refers to Statement 1 and says "As mentioned earlier, the method remove compares the objects for equality before removing it from ArrayList by calling method equals."
Java Code:
import java.util.ArrayList;
public class DeleteElementsFromArrayList {
public static void main(String args[]) {
ArrayList<StringBuilder> myArrList = new ArrayList<>();
StringBuilder sb1 = new StringBuilder("One");
[Code] ....
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Jun 22, 2014
I would like to create a java gui (with CRUD elements) that connect to MySQL server DB and display a table records (also insert, edit, delete data to table), and I want to know how create such a gui.
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Oct 27, 2014
So I am trying to create a code that searches if a word is square free. The user inputs a word (into an array) and then the code is suppose to see if it is square free. A word being square free means that the word doesn't contain any consecutive sub words. For example, "abcabc" is not a square free word because abc is repeated, but "abcdabc" is a square free word because there is a "d" separating the "abc".
So far I have this :
import java.util.Scanner;
public class A3Q2 {
public static void main(String[] args) {
// part (a) of the main
Scanner keyboard = new Scanner(System.in);
[Code] ....
I've been trying to experiment with different ways such as checking to see if there any duplicate elements such as,
public static char isSquareFree(char[] word){
for(char i = 1; i < word.length; i++) {
if(word[i] == word[i - 'a']) {
System.out.println("Duplicate: " + word[i]);
}
}
return word; }
}
And other methods but I'm just not getting it.
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Feb 6, 2014
Here is a small part of my program
Java Code:
// for every attribute not mentioned in the rule r
enumAtt = ruleE.enumerateAttributes();
while (enumAtt.hasMoreElements()) {
Attribute attr = (Attribute) enumAtt.nextElement();
if (isMentionedIn(attr, r.m_test)) {continue;}
int M = attr.numValues();
[Code] ....
It repeats only the last rule , why is that !!!!!!
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May 11, 2015
I have a 2D arraylist, named as adjLists, which contains arraylists, containing values like these. Each two values are a "pair" and each third is a "flag" for the pair.
[278, 106, 0, 397, 36, 0, 59, 208, 0, 366, 221, 0]
[366, 221, 0, 397, 36, 0, 132, 390, 0, 278, 106, 0, 295, 0, 0]
I use code above to search for specified value pairs in these lists. vertexnum is the number of "sub arraylists" in adjLists.
for (int l = 0; l < vertexnum; l++) {
if (adjLists.get(l).get(0) == p.x && adjLists.get(l).get(1) == p.y) {
for (int h = 0; h < adjLists.get(l).size(); h += 3) {
for (int g = 0; g < vertexnum; g++) {
if ((vertexSprite[g].getX() + vertexSprite[g].getWidth() / 2) == adjLists.get(l).get(h)
[Code] ....
This code is to search exact values and replace their flag in every occurences. It can not find all the occurences of the values/pair in the lists, it replaces flag value only a few time. Value of score should be incremented with plus 1 after each found occurence, but this code increments it more than the number of matches.
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Feb 14, 2014
i have the following code to reverse the elements of the list but i only print the last element each time
public void reverse(OrderedList<T> lister) {
OrderedList<T> listerCopy = lister;
for(int i=0;i<5;++i) {
T removed=removeFromBack(listerCopy);
System.out.printf("%s ", removed);
[Code] .....
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Mar 25, 2015
I'm currently in the process of creating a shopping cart simulation. The main GUI consists of two lists, one is a list of the inventory. (products stored within a .dat file which is automatically loaded upon launch) The other is blank and is to model my shopping basket. The idea is to be able to scan items from my inventory into the checkout basket. As this is happening i want a text field i created to dynamically update with the cost of all the items in the basket.
Below is the method for my scan button, which is supposed to perform the above :
public void actionPerformed(ActionEvent evt) {
//Get the newly added list values.
JList list = productList.getSelectedValuesList();
double totalAddedValue = 0.0;
double oldCartValue = 0.0;
[code]...
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Apr 27, 2014
ok so for class I'm supposed to Write a class DeleteElements that prints out an array and asks the user which number should be deleted and then deletes that number, if it exists from the array.
The first part tells me to
Step 1
o Start by simply searching the element.
o Pseudocode:
-Create an array and populate it with random positive integers.
-Print the array to show the user which elements the array contains.
-Use a WHILE loop to search the element—a WHILE loop is better than a FOR loop because you can stop when the element is found by using a Boolean value in the loop condition—and also keep track of the location where the
element might be found.
-If the element is not found, output the error message, “Number not found.”
-Otherwise output the message, “Number found at index #.” where # is the index where the element is.
-Print out the array.
Example of output:
34 65 12 76 45 39 86 71 67
Number to delete: 76
Number found at index 3
This is what I've got so far but I can't seem to get the "number not found part to print out only once".
import java.util.Arrays;
import java.util.Random;
import java.util.Scanner;
public class DeleteElement {
public static final int ARR_LENGTH = 10;
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
Random ran = new Random();
[Code] ....
Current output result if value does not exist:
61 89 52 16 20 71 37 91 4 36
Number to delete:
23
Number not found.
Number not found.
Number not found.
Number not found.
Number not found.
Number not found.
Number not found.
Number not found.
Number not found.
Number not found.
Current output result if value exists:
97 48 51 22 89 5 42 97 43 96
Number to delete:
89
Number found at index 4
Maybe I'm not understanding the part about the boolean value.
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Oct 15, 2014
I have tried to print array elements using standard print statement. I am getting errors. How to print them. Here is my code:
class arrayEx1{
public static void main(String args[]) {
int a[]=new int[3]; //Declaring Single Diomentional Array
a[0]=10;
a[1]=20;
a[2]=30;
int total=a[0]+a[1]+a[2];
System.out.println("Values stored in a[0],a[1],a[2]elements are :" + a[0] a[1] a[2]);
System.out.println("Total values of a[0],a[1],a[2]elements is :"+ total);
}
}
if i give comma (,) in between above print stament (print statement 1) stil i am getting errors.
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Nov 19, 2014
Currently I am having difficulties styling a particular prime faces element in a JSF application for work. I'm tasked with giving the ui a styling and color scheme acceptable to our project design. However I am finding myself unable to "hook" a particular pf element with an ID so that I can proceed with styling a imported .css file.
I'm trying to style the commandLink button to display in Orange 20px font with Italic but when I inspect the element in chrome after being rendered It doesn't even show its style linked to the assigned ID. The class style for mainMenuItem is being applied to the commandlink but is immediately over written by ui-widget. I'm trying to style that one single component(override/replace ui-widget with the properties in the #loggedInUserID)
Current .XHTML code and the css file has been linked with
<h:outputStylesheet library="css" name="masterPW.css"/>
<div class="mainMenuItem"><p:commandLink id="loggedInUserId" styleClass="maserPW.css" value="#{loginController.userFullName}"/>
</div><!--End of mainMenuItem-UserID div -->
[Code] ....
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Mar 20, 2014
public class werek4d {
public static void main(String[] args) {
int counter = 1;
int[] anArray = new int[101] ;
for (int i = 0; i <= 99; i++){
anArray[i] = i + 1;
System.out.println(i + ": " + anArray[i] + " ");
[Code] ....
My aim is to generate a lists containing 1 to 100. I will then count the number of integers divisible by 3. After doing so, I want to delete the integers that are NOT divisible by 3 in the lists. I tried doing it, but I seem to keep on getting the same lists.
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Dec 27, 2014
I have an ArrayList of tens of thousands of elements, and want to remove the items at a given set of sorted indices like {1,5,29,318,499,583}. It seems like this operation could be performed in linear time and space by first finding a cumulative sum of the shifts needed to move everything to their right positions and then shifting every item. On the other hand, removing and shifting one by one would seem to require many more shifts. Is there a way to do this in Java's ArrayList?
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Apr 1, 2014
I am working on a assignment that has to do with array lists, it mainly has to do with adding new elements, telling then where it is it located, if the memory block is empty , ect. so far i have been having problems with my indexOf method which should display the array cell number that a input element E is in, and if it is not in there it should display a -1.
public class MyArrayList<E>
{
private E[] data_store = (E[])new Object[2];
private int sizeofa = 0;
private void resize()// makes the array list bigger if need {
E[] bigspacemaker = (E[])new Object[data_store.length * 2];
for(int x = 0 ; x< sizeofa ; x++)
[Code] ....
Error message:
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 512
at MyArrayList.indexOf(MyArrayList.java:28)
at MyArrayListDemo1.main(MyArrayListDemo1.java:26)
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Apr 6, 2015
I have two ArrayLists and I want to compare them for common elements, and based on the result I want to update the first Arraylist to only have these elements. sort of like the opposite of RemoveAll() which removes elements in common and keep the ones that are unique. so far I thought of using for loop and .contains() in case it was fault,element not present, remove from list. but I was wondering
in what other ways, perhaps APIs i can use to do that?
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Jan 8, 2015
Lets suppose that I pass to the sort method a list of 2 objects of the same class (which implements Comparable interface). I read (in head first java) that one object is compared relative to another with one object calling the CompareTo() while the other object being passed as a parameter to the same method. Now am I safe in assuming that the first object in the list calls the method with the second object being passed as a parameter.And also how does the CompareTo() work if there are more than 2 elements in the list. Which objcet calls the method and which is passed as a parameter?
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Oct 5, 2014
When this program runs it gives me
workbook.Contact@46e5590e
Number of contact: 1
The number of Contact that I input is just one when I run the program so the Number of contacts: 1 is correct, but it gives me workbook.Contact@46e5590e instead of printing out all the contacts stored inside the Contact class. Yes I do loop through the ArrayList and I also have a method inside the Contact class, the printNameAndPhone(), which prints out the name as well as the phone number but how do I incorporate the printNameAndPhone() method (located in the Contact class) inside the print() method (located inside the AddressBook class)???
Basically I'm asking how to access all the elements in the ArrayList<Contact> addressBook = new ArrayList<>();??My main class AddressBook
package addressbook;
import java.util.Scanner;
import java.util.ArrayList;
public class AddressBook {
[code]....
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