Why Does Removal Of Boolean Test Result In Different Answers
Mar 15, 2014
I'm trying to find all of the prime factors for a given number. The following code achieves this:
private static ArrayList<Long> findPrimesOf(long number) {
ArrayList<Long> primes = new ArrayList<>();
long highestDivisor = (long)sqrt(number);
for (long divisor = 2; divisor <= highestDivisor; divisor++) {
if (number % divisor == 0) {
boolean isPrime = true;
for (long i = 2L; i < divisor; i++) {
if (divisor % i == 0) {
isPrime = false;
break;
[code]....
However, if I remove the boolean test isPrime, as below, I get additional numbers after the highest prime factor.
private static ArrayList<Long> findPrimesOf(long number) {
ArrayList<Long> primes = new ArrayList<>();
long highestDivisor = (long)sqrt(number);
for (long divisor = 2; divisor <= highestDivisor; divisor++) {
if (number % divisor == 0) {
for (long i = 2L; i < divisor; i++) {
if (divisor % i == 0) {
break;
[code]....
I can't work out why this should be. From my understanding, the divisor only gets added to the list of primes if the loop doesn't break (which, with the boolean test would be true anyway).
I am working on a program that simulates someone logging in. For this program, I have three methods:
public void input(String text) public void click(String button) public boolean loggedIn()
Naturally, the default status of loggedIn() is false, but I am having trouble changing the boolean to true when a user has successfully entered a username and password.
Specifically,
public void click(String button) { Button = button;//Button is declared at the beginning of the class if(Button == "Submit") { //Statement that changes loggedIn() from false to true when the user clicks the "Submit" button. }
No matter what I try, I get various errors about how what I tried was illegal.
I've been scanning forums for answers to this problem, but most deal with simple programming that you might find in a classroom (i.e. "System.out.printf") which will not work in the GUI I'm attempting to complete. Here's the tale of the tape:
The GUI is a price calculator I'm developing for my company that takes input from drop-down menus and several Jtextfields and calculates the answer based on the values contained within each. It's completely done (and functional), so I'd rather not change too much if at all possible. Because I'm dealing with decimal values then I'm getting 9 decimal places in the output JLabel, though. In order to display the answer, I'm using a series of "totalPrice.setText(..." declarations.
Because there is a fair amount of text and the values in the calculation are constantly changing, is there a way to 'simply' format the output JLabel to display only 2 decimals? Or is there an alternative solution that would work--say with a JTextfield instead--without having to completely re-code the calculator?
When one is needed I simply add it to the table. In this case however whilst updating the model via table update in tableChanged method I have the impression of 2 identical models because the update happens twice (use of audio).
Is it not true that adding a new model cancels out the other ? I test for which model is attached to table and add the correct one depending on the data required.
How do you remove from an ArrayList at a particular index then add back to that same index without the removal causing the ArrayList to compensate for the loss of them item and moving the empty space to the end of the array list?I've tried:
public void dischargePatient(int bedNumber) { if (bedNumber < beds.size()) { beds.remove(bedNumber); } }
But this moves the bed at bedNumber to the end of the ArrayList after removing the patient from the bed. How do I keep it at bedNumber?
I can often write a recursive backtracking solution, but don't know how to cache the answers into an appropriate array.
For example:
Java Code:
public static int max(int[] costs, int index, int total, int shares) { if(index >= costs.length) { return total; } int buy = max(costs, index + 1, total - costs[index], shares + 1); // buy one stock int sell = max(costs, index + 1, total + shares * costs[index], 0); // sell all stocks return Math.max(total, Math.max(buy, sell)); // compares between buy, sell, and doing nothing } mh_sh_highlight_all('java');
This is a dynamic programming exercise, but I have no idea what dimensions the dp array should be (I was thinking maybe dp[index][total][shares], but that seemed like overkill). Is this just because my understanding of recursion isn't solid enough or am I missing something else?
I am making a program which accepts two user inputs one being a letter either upper or lower case and the other being a number. the out come should be some thing like this:
G GG GGG GGGG GGGGG
This is assuming the user inputted 'G' and '5'.
here is the code i have so far:
package week10; import java.util.Scanner; public class integer { public static void main(String args[]) { Scanner user_input = new Scanner( System.in );
[Code] ....
The problem i am having is that i cant get the number that is inputted to be accepted as a variable to be used for the program.
how to determine if an integer is even or odd by using a boolean method. I think I have the method right, but it's calling the method into the main that has got me stumped.
import java.util.Scanner; public class Odd_Even { public static void main(String[] args) { //Scanner, variables Scanner input = new Scanner(System.in); int number;
So I'm trying to check if the new coordinates vs original coordinates are diagonal and 1 line further, and if there is a piece there(getNum()) if it's 2 lines further, so I'm trying to return a boolean value then.
so if it's the first if, it returns true, if it's the 2nd it returns true, then I say else for all other scenario's, and return false there, but my compiler says my method is missing a return statement.
public boolean check(int[] d) { int x,y; x = loc[0][0]; y = loc[0][1]; int sx = d[0]; int sy = d[1];
[Code] .....
Edit: used a local boolean and returned that after my if's.,
code=Java import java.util.Random; import java.util.Scanner; public final class Derp { public static int WIN, Tick; public static Scanner Input = new Scanner(System.in);
[code]...
why this boolean statement isn't working correctly. It's not detecting that the WIN and Tick are the same and instead chooses to always run the second statement.
I have this project due and its asking that i print out what type of triangle it is when the user inputs 3 sides. I have most of it done and working, but it pops up different windows instead of using one window for everything. The assignment says it needs all the final info to be in one window. The boolean is coming from another method. I'm unsure how to get it into a string (Or if that's what i have to do). The method must return a boolean true/false.
import javax.swing.*; public class Triangle { public static void main(String[] args) { int side1 = getSides(); int side2 = getSides(); int side3 = getSides();
I read in a book that when you change the value of a method parameter that's a boolean or other basic datatype within the method it only is changed within the method and remains the same outside. I want to know if there is some way for me to actually change it within the method. For example:
public class Change { void convert(boolean x, boolean y, boolean z) { //i want to set x,y, and z to false in this x = false; y = false; z = false;
[code]...
I want to put in part1, part2, and part3 when i call the method than i want them to be set to false within the method. The specific reason i asked this question was because im trying to code a battleship and i have a subroutine class with a method that when its called it checks if a ship has been sunk. If the there was a sink than the method will set a ton of boolean variables to false.
Just to clarify, I want something like this:
void convert(thing1,thing2,thing3,thing4) { //some code here that sets thing1,thing2,thing3, and thing4 to false } // than in main: boolean test1 = true; boolean test2 = true;
I wrote a class for encapsulating coins and I was to do a boolean statement but when I test the statement the results are not showing.Here is the code for my coin class coins.java
package project_3; /** * * @author user a */ public class Coins { private double pennies; private double nickles ; private double dimes ; private double quarters ; private int dollars ;
I want to write a program that ask if you want to go to the movies. If the user type in yes then it'll print out (Alright let go) but if the user type no then it would print (whatever). The trouble that I'm having is. What's the best way to use Boolean and Strings together in a if statement?
public class Night { static Scanner UserInput = new Scanner (System.in); public static void main (String [] args){ boolean user1, user2; user1 = true; user2 = false;
package Week_8; import java.util.Scanner; public class Task_1 { public static void main(String[] args) { Scanner kboard = new Scanner(System.in); int customer_number; String customer; int items; char category;
Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Boolean at javax.swing.plaf.synth.SynthTableUI$SynthBooleanTa bleCellRenderer.getTableCellRendererComponent(Synt hTableUI.java:731) at javax.swing.JTable.prepareRenderer(JTable.java:573 1) at javax.swing.plaf.synth.SynthTableUI.paintCell(Synt hTableUI.java:684)
Boolean retrieval model using skiplist. I don't know how to code it. I have modified it but I'm not sure it work out. What are the modifications I can made.
/**My requirement is to implement two methods for Boolean Retrieval:
● index(String dir) ○ index()supposed to go over all files under "dir". There will be no subdirectories inside it.
● retrieve() ○ retrieve() supposed to return name of all the documents under "dir" that satisfies the given query. Note that, only basename of the files are to be returned, not the full path. ○ Query can be of two forms: ■ OR: returned doc should contain at least one term from the query. ■ AND: returned doc should contain all the terms from the query. **/
import java.util.HashSet; import java.util.Vector; public class BooleanRetrievalModel implements DocSearch { // begin private class private class SkipList { // Node in skip-list
I reserved one row for first class and another for economy class. This code works just as I want but my question is how can I loop through it so I don't need all the if statements? I tried it many ways. I tried something like this but I cant get it to work.
for (int row=0;row<seat.length;row++{ for (int col=0;col<seat[row].length;col++){ if (seat[0][col]==false){ seat[0][col]=true; System.out.println("You have number 0" + row + in first class);
If I have a boolean array that contains 30 elements (boolean[] fish), how do I go about isolating every 10 elements to use for something specific?
Say there are 30 types of fish stored within the boolean array and 0-9 are fish found specifically in the Indian Ocean, 10-19 are fish found specifically in the Atlantic, and 20-29 are fish specifically found in the Pacific Ocean. And for those 10 fish [0-9], [10-19], [20-29], each is a different color (red, orange, green, blue, white, black, silver, yellow, purple and gold), where the colors and locations of the fish are enum types Colors and Locations.
How do I go about appointing those characteristics to the fish?
Ex: elements [0-9] are fish from the Indian Ocean and [0] is red, [1] is orange, [2] is green, [3] is blue, [4] is white, [5] is black, [6] is silver, [7] is yellow, [8] is purple, and [9] is gold.
elements [10-19] are fish from the Atlantic Ocean and [10] is red, [11] is orange, [12] is green, [13] is blue, [14] is white, [15] is black, [16] is silver, [17] is yellow, [18] is purple, and [19] is gold.
elements [20-29] are fish from the Indian Ocean and [20] is red, [21] is orange, [22] is green, [23] is blue, [24] is white, [25] is black, [26] is silver, [27] is yellow, [28] is purple, and [29] is gold.
Will I need to appoint those characteristics in the constructor after initializing fish = new boolean[30]?
Create an abstract class called Student. The Student class includes a name and a Boolean value representing full-time status. Include an abstract method to determine the tuition, with full-time students paying a flat fee of $2,000 and part-time students paying $200 per credit hour. Create two subclasses called FullTime and PartTime. Create an application that demonstrates how to create objects of both subclasses."
public abstract class Student { private String name; private int credits; public Student(String name){ this.name = name; credits =0;
I need to do a rectangle using boolean array where true elements are the borders of the rectangle, and false elements are the inner space. I imagine that the first and last rows and columns must give the true element,
public class Functionality { public static boolean[][] rectangleArray(int n, int m){ boolean[ ][ ] matrix = new boolean[n][m]; for(int i = 0; i <matrix.length; i++){ for(int j = 0; j < matrix[i].length; j++){
Boolean retrieval model using skiplist. I don't know how to code it. I have modified it but I'm not sure it work out. What are the modifications I can made.
/**My requirement is to implement two methods for Boolean Retrieval: ● index(String dir) ○ index()supposed to go over all files under ‘dir’. There will be no subdirectories inside it. ● retrieve() ○ retrieve() supposed to return name of all the documents under ‘dir’ that satisfies the given query. Note that, only basename of the files are to be returned, not the full path. ○ Query can be of two forms: ■ OR: returned doc should contain at least one term from the query. ■ AND: returned doc should contain all the terms from the query. **/
import java.util.HashSet; import java.util.Vector; public class BooleanRetrievalModel implements DocSearch { // begin private class private class SkipList { // Node in skip-list
