Accurately Converting Units Involving Extremely Small Numbers?
Jun 16, 2014
I need to convert units accurately. Some of these units include angstroms (0.1nm) and astronomical units or light years. I can't seem to accurately perform these equations (probably mostly because of lack of a proper conversion formula). For example:
1 angstrom = 1.79985601 × 10^-14 leagues (or, 0.00000000000001799856 leagues).
To perform the conversion right now, I'm simply multiplying the angstroms by 0.00000000000001799856. However, inputting 55560000000000 (angstroms in one league) results in 0.9999999936. Why is this? Is it possible to work around it? I believe there's a term for the inability for a computer to process 1/3rd properly, but I can't remember what it's called - is that the problem?
I am using BigDecimals for all equations.
Edit: a mod can change the title if they think another is more fitting.
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Dec 8, 2014
I'm currently taking a computer science class but the class is moving extremely slow and I'm not learning much, so I've started to program on my own. The most recent project I've done is a tic tac toe game, and I'm looking for something else to do now. I can do with an increased difficulty from this project, but not extremely difficult.
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.lang.reflect.Array;
[code]...
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Jul 7, 2014
I found an open-source recipe for converting numbers to words.
I modified it a bit since the requirement is only for integers until 999:
public class NumberToWordsConverter {
private String[] ones = {"zero", "one", "two", "three", "four",
"five", "six", "seven", "eight", "nine", "ten",
"eleven", "twelve", "thirteen", "fourteen", "fifteen",
"sixteen", "seventeen", "eighteen", "nineteen"};
[Code] .....
From robosoul's response at StackOverflow, I simply inserted a condition for negative integers (line 12). True enough, the code worked and I was able to trace (pen and paper method) how it is converting the 0 and positive integers to words.
However, I am a bit lost on how it is doing the conversion for negative integers. How it is successfully converting the negative?
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Mar 17, 2015
Convert to following sysntax (from Matlab) having complex nos.
real((413000*atan((T^(1/2)*((4130000*V*1i)/(139*T^(1/2)) + (413000*1i)/T^(1/2)))/413000)*1i)/(139*T^(1/2)))
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Sep 8, 2014
I have a maths application I am working on in java. This is more related to maths but there could be some here who have worked with calculations like this in their java project.
One could convert from degree to radians and from mph to knots. Could one convert from knots to degree or from mph to degree?
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Feb 19, 2015
How I am supposed to set up the units for my program, and how to correctly display them in the console. Here is a description of my program.
To display the nonzero denominations only, using singular words for single units such as 1 dollar and 1 penny, and plural words for more than one unit such as 2 dollars and 3 pennies. You must use nested if statement when displaying the output.
Sample run:
Enter an amount in double, for example 11.56: 1.56
Your amount 1.56 consists of
1 dollar
2 quarters
1 nickel
1 penny
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Aug 31, 2014
I just started programming yesterday, and I have been making little programs to learn some algorithms and the syntax of java. I tried making a program that could convert metric units into the American system. Whenever I try to compile the code, it shows up as an "incompatible type" error. I know this is probably a very obvious answer to most of you, but I can't figure it out.
import java.util.Scanner;
public class MetricToAmerican
{
public static void main(String[] args)
{
Scanner scan = new Scanner(System.in);
System.out.println("fWhat measurement would you like to convert into US system?
celsius, meter, or kilogram ");
[code]....
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Feb 9, 2014
I am trying to write a program that basically determines the max amount of units sold and displays it in a dialog box. Also, the program will display the winning sales associate out of 10. I have wrote the program successfully so far and I can see the maximum number of units sold displayed in the dialog box, but I cannot seem to link the winning sales person.
Here is the code I have typed so far.
//Program to find maximum of three number
import javax.swing.JOptionPane;
import java.util.Scanner;
public class Sales
{
public static void main (String[] args)
{
//Declare variables
int num1, num2, num3, num4, num5, num6, num7, num8, num9, num10;
int large;
int winner;
[Code] ......
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Feb 4, 2014
Me and my brother are working on a small java project to learn network programming and get some experience working with networking code. We decided to make a relatively simple client/server program where clients get into a simple chat lobby and can invite others to play small games(like pong). The basic server code has been written, and we have made a special client that is used for debugging.
We use a self-defined protocol of Strings where a message looks like "4-|user,pass". The number before the delimiter "-|" is the operation code, that tells the server what kind of message this client sends. Based on that number, the server dispatches the message to the appropriate handler method. 4 is authentication for example, and the handler looks the user and pass up in a file and if found, returns true, otherwise, false. Then the server responds to the clinet with 2-|"any message" where the client will recognize opcode 2 as a "authentication accepted" and proceed with the next part of client code. In a similar way, we plan to write all message types(both in the game, in the lobby and in a game setup room).
While testing we ran into a problem where the BufferedReader .readLine() does not seem to be a blocking call like it should be, so the client keeps spamming 'null' in the output field that we made to see the server response to the message we send. When we try to debug the server code and set breakpoints at the suspicious locations, it strangely skips both while(true) loops without activating either breakpoint and executes the finally{} code, even though the client did not close the connection and the second while loop was never entered. The first while loop IS entered though, because the test client gets a "0" on its output, which is the server message indicating "please authenticate yourself".
Also, if we approach things in a dumb way that can be done way more efficiently or easier to read/manage, please do tell. Keep in mind we are beginners though! We decided to use messages in a string format and decode it at both sides as it seemed easier than transmitting java objects and making sure they are of the same type, also for reducing overhead as much of possible. URL....
The server code:
package Chatroom;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashSet;
/**
* This is the main server class. It is the core of the server functionality, and the listener for incoming clients that will spawn threads to deal with clients, track their information, change their states and ultimately, clean up after all clients by keeping the data structures up to date.
[code]...
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Jun 23, 2014
I'm having a problem with a small text editor I'm trying to create. I have implemented a panel of labels, containing line numbers, on the left of a scrollable text area. The panel is designed to size such that it fits the larger numbers whenever they appear. It does that very well, actually, until either one of the scrollbars appear. As soon as one does appear, it immediately shrinks in width. The horizontal scrollbar even blocks the view a little, making it impossible to see what you are writing on the very last line.
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Main implements KeyListener {
public static JPanel tab = new JPanel(false);
public static JTextArea text = new JTextArea();
public static JScrollPane scroll, reflex;
public static JPanel lines;
[code]...
Explanation of the code: There is a main panel which embodies a text area and another container filled with labels of line numbers.Both the text area and line number panel have scroll panels attached. They are synchronized, in order to scroll at the same time.
The main class contains a static function "position" which generates a GridBagConstraints, created for the convenience of single-line creation of constraints.It also implements the KeyListener interface, and waits for change in the amount of lines inside the text area. Afterwards, it changes the panel of labels accordingly.
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Dec 18, 2014
i'm totally new to Java.I'm making a small text based RPG and this is what i've come up for now.
Java Code:
import java.util.Scanner;
class Main {
public static void main(String args[]){
Scanner input = new Scanner(System.in);
Player playerObject = new Player();
[code]....
My thing is that i want the user to enter 'Caucasian' or another race in the console below and i want it to be saved in a variable or something else in the Player Class that i can later use it in texts or something else. My question is how can i do it?
I tried like 'int Mongoloid = 1; int Caucasian = 2;'
And the same with the others, and after that i tried to use them with the Switch Statement but it did not work.
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Mar 3, 2014
I'm fairly good at Java, but somewhat at a loss when the some of the JavaScript below is mentioned. I've attempted to port the below code, but I'm finding it somewhat difficult.
Parts of JavaScript I'm stuck at porting:
1. I'm stuck on the return statement on the 3rd line.
2. Similarly the lines utilizing "charCodeAt", as I keep getting error "Cannot invoke charCodeAt(int) on the primitive type char"
3. Also on the second to last line, I keep getting the error "Cannot invoke padLZ(int) on the primitive type int".
Link to original javascript
Convert between Latitude/Longitude & OS National Grid Reference points
Original JavaScript
Java Code:
OsGridRef.prototype.toString = function(digits) {
digits = (typeof digits == 'undefined') ? 10 : digits;
e = this.easting, n = this.northing;
if (e==NaN || n==NaN) return '??';
// get the 100km-grid indices
var e100k = Math.floor(e/100000), n100k = Math.floor(n/100000);
[Code] ....
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Jan 24, 2014
I am trying to write a small program that will calculate the gain and/or loss of the sale of stock. The program will ask the user for the number of shares, the purchase price and the selling price. I am pretty sure that the errors is coming from my calculations in the program.
import java.util.Scanner;
public class investmentCalculator {
public static void main (String[] args) {
Scanner input = new Scanner(System.in);
//User input for number of shares
System.out.print("Enter the number of shares: ");
double shares = input.nextDouble();
[code]....
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Oct 9, 2014
My instructions are to:
1. Prompt the user to input two positive integers: firstNum and secondNum (firstNum must be smaller than secondNum).
2. Output all the even numbers between firstNum and secondNum inclusive.
3. Output the sum of all the even numbers between firstNum and secondNum inclusive.
4. Output all the odd numbers between firstNum and secondNum inclusive.
5. Output the sum of all the odd numbers between firstNum and secondNum inclusive.
*Use while loop
int firstNum, secondNum;
Scanner keyboard = new Scanner(System.in);
System.out.println("Enter an integer: ");
firstNum = keyboard.nextInt();
[Code] ....
What to do with the while loop and how to find even and odd numbers.
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Jan 29, 2015
As a result I need to get 6 66 666 6666 66666, but I'm getting a mistake. Can anb explain what's wrong?
Java Code:
public static void main(String [] args)
{
int[] sixes = new int [6];
for (int i = 0; i < sixes.length; i++)
{
sixes[i] = i * 10 + 6;
System.out.print(sixes[i]);
}
} mh_sh_highlight_all('java');
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Mar 2, 2015
public class School {
public final int MIN_GRADE = 0;
public final int MAX_GRADE = 100;
private int [] grades;
public School( int students ) {
grades = new int[students];
[Code] ....
The output is :
The numbers in the array are: 1 2 3 4 6 7 8 9 10 13 14 15
The highest grade is: 11
For some reason it is not giving me the highest number in my array. Did I write the method wrong ? Is my array even passing through HighestGrade ?
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Jan 31, 2014
I have created a text file that contains a small list of toy names and prices, like:
Barbie, 12.95
Lego, 15.99
Hot Wheels, 5.00
Power Rangers, 6.49
And what I would like is my application to read the contents of the file and store the toy names in a list component. And then I want to be able to select a toy name from the list and add it to a shopping cart that is a list component as well. I want to the application to have menu items and buttons to allow me to remove items from the shopping cart, clear the shopping cart of all selections, and check out.
When I check out, the application should calculate and display the subtotal of all the toy names in the shopping cart, the sales tax (which can just be 8 percent of the subtotal), and the total. create this simple application example I've just made up, and I'm going to add and use this example to create a bigger application myself.
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Oct 23, 2014
Alright so I'm trying to write a code that implements a for loop and if statements that displays any number from 100-200 if the number is divisible by either 5 or 6 in rows of ten numbers each row. If it is not divisible by that number then it should go back to the beginning of the loop until it reaches 200. My main problem is that it doesn't display anything. I don't get any errors or anything but every time I run the program it just displays nothing. Sample output is at the bottom of the code.
public class Exercise5_11 {
public static void main(String[] args) {
int count = 0;
int i = 100;
//for (the numbers from 100 to 200)
for (i = 100; i>100 && i<200; i++){
[Code] ....
/*Output
100 102 105 108 110 114 115 125 126 130
132 135 138 140 144 145 155 156 160 162
165 168 170 174 175 185 186 190 192 195
198 200
*/
It is still wip of course so I was trying to just get it to display int i but it doesn't do anything and I'm not really sure why.
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May 14, 2014
So I want the method getDisplayText of d to be returned as long as the for loop runs. When I do this I get a compile time error to enter a return statement. I am currently trying to fix it by returning an empty string, yet this doesn't seem the right way to go.
public static String displayMultiple(Displayable d, int count)
{
for(int i = 1; i <= count; i++)
return d.getDisplayText();
return "";
}
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Nov 26, 2014
I'm working on a project that involves the following:
-Creating a superclass of bankaccounts
-Creating two subclasses, checkingaccount and savingaccount
-Each of the two subclasses has different methods (writeCheck for checking, for example)
-Both types are created in a main class bank and stored in the same array
So let's say a user goes through the menus and creates a few savingAccounts and a few checkingAccounts (stored in the accounts[] array). Then, to write a check from one account, the user can enter the account number (a string), and the method will use a for loop to cycle through the array until it hits an account number match. Then it checks that it's the correct account type and calls methods from the subclass.
Problem here is that some methods work and some don't. In the following example:
for (BankAccount account: accounts) {
if (account.getAccountType().equals("Checking")) {
do {
if (account.getAccountNumber().equals(accountNumber)) {
amount = Double.parseDouble(JOptionPane.showInputDialog(
[Code] .....
The getAccountNumber method works but writeCheck is throwing an error. I tried creating a method in the superclass and overriding it in the subclasses but with no success.
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Feb 1, 2014
I am learning Java on my own and I am taking on very small project by myself for fun, and I'm just stuck on this small part of the project.
So I have created a text file that contains a small list of toy names and prices, like:
Barbie, 12.95
Lego, 15.99
Hot Wheels, 5.00
Power Rangers, 6.49
And what I would like is my application to read the contents of the file and store the toy names in a list component. And then I want to be able to select a toy name from the list and add it to a shopping cart that is a list component as well. I want to the application to have menu items and buttons to allow me to remove items from the shopping cart, clear the shopping cart of all selections, and check out. When I check out, the application should calculate and display the subtotal of all the toy names in the shopping cart, the sales tax (which can just be 8 percent of the subtotal), and the total.
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Apr 4, 2014
1. Modify the following class so that the two instance variables are private, there is a constructor that accepts both the player's name and sport and there are get and a set methods for each instance variable:
public class Player {
String name;
String sport;
}
2. You can pass an instance of this class to the JLabel constructor if you want to display text in the label.Select one:
a. myLabel
b. myText
c. String
d. JTextField
e. JLabelText
how to start making this work?cause i am not familiar with the terms here and want to complete this program and I am new to java programming?
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Oct 25, 2014
I'm not sure if my understanding of PriorityQueues is correct, so I'm trying to check if my reasoning is valid. I'm supposed to compare the Big-O for arrays and linked lists for the following instructions:
Insert 100 objects having the priorities 1, 2, 3, ... , 99, 100
Big-O for Array: __________
Big-O for Linked List: ___________
Insert 100 objects having the priorities 100, 99, 98, ... , 2, 1
Big-O for Array: __________
Big-O for Linked List(Assume no tail reference): ___________
If my understanding is correct, priority queues take in items randomly with no particular order, but they are removed according to the priority of each element. If what I've said is true, wouldn't that mean that inserting any number of objects would be O(1) for both linked lists and arrays? If the PriorityQueue has no particular order, then wouldnt each add() simply insert something to the next array index/linked list node?
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Jan 25, 2014
I'm writing a program for exemplary reasons that is basically two text fields, one for a username, and one for a password. the way its written is asking testing for what is inputed into the text fields if its equal to a "valid" username and password. if it is, a variable representing that is set equal to 1. there is another if statement asking if the actionevent.getsource is equal to the name of the textfield. the issue I had was that when I ran the program, it seemed to only test for the first condition, so I got the same result from the program regardless of what I input into the text field.
The Code
Main class:
import javax.swing.JFrame;
public class Alpha {
public static void main(String args[]){
log l = new log();
l.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
l.setSize(360, 240);
l.setVisible(true);
[Code] .....
The code originaly was written "eve.getSource() ==" but I changed that to see if it would resolve the issue with no avail. With it written this way, the program does nothing upon entering the text and pressing enter. Currently, there is nothing written to change the variable "val" to 1 to show that the username is valid. I did this because I can't figure out how I would go about doing this.
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Oct 22, 2014
I have a problem with functions connected to strings.
I have a random String, e.g. "Hello World!" and I have to change every capital Letter into a small letter and vise versa. This alone would be fairly simple, but I have to do it with two other strings.
lowercase= "abcde...z" and
uppercase="ABCDE...Z". Every small letter stands at the very same position as the capital letter, but in the other string.
There should be a letter for letter search in lowercase and uppercase for the letters of "Hello World".
How I could solve the task, however I need a way to search the first string, here "Hello World", according to position. A statement which does: "Give me the letter of position x". This found letter should be able to be stored in a variable or else be able to be used by another statement. And it should be compatible with a for lope.
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Aug 22, 2014
I tried to create file and write the output of my program in it in java when i use WriteLong then the file does not contain long value, how I create this file my program is to print prime numbers between 500000 to 10000000
public class primenumber {
public static void main(String[] args) {
long start = 5000000;
long end = 10000000;
System.out.println("List of prime numbers between " + start + " and " + end);
for (long i = start; i <= end; i++) {
if (isPrime(i)) {
System.out.println(i);
[Code] ....
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