Initializing Variable Within Program
Mar 3, 2014
My objective is to write a program that calculates the bodyfat of people. The difficult thing is, that the calculations are different for males and females, so I tried to prompt the user to state whether they are male or female, then use and "if" statement to tether their response to the corresponding calculations.
Here's my algorithm:
Here's what I have:
package bodyweight;
import java.util.Scanner;
public class Weightcalc {
static Scanner console = new Scanner(System.in);
public static void main(String[] args){
[Code] ....
It keeps telling me that bodyweight is not initialized, but when I do, I get a hell of a lot more bugs on everything telling me they aren't initialized. I just want the program to transfer the user to select inputs, based on whether they are male or female.
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Oct 12, 2014
I don't understand that the error occurs when I don't initialize the variable myPoint. Whereas, I initialize the variable myPoint after variable declaration and before place of error.
package enumeration;
import java.util.Random;
public class Craps {
[Code]....
When I initialize the variable myPoint to zero in its decleration, the error disappear. But why? I have already initialized the variable myPoint in default case before the line of error occured..
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Feb 26, 2015
I am new to JSP and I'm having a problem with captcha containing a value in the field when toggling from the first page to another and clicking submit on the second page before entering data to validate the fields and the code just falls through and returns the error "Please enter the correct code". The values returned are (captcha)96043 (code)null, captcha is not null because it is retrieved from session which is the last value captured from the page I'm assuming.
I've used request.getSession().removeAttribute( "captcha" ); before building the page to clear out the values, resetting captcha to null etc.; nothing is working.
Here's the code:
boolean isPostBack =false;
String captcha = (String) session.getAttribute("captcha");
String code = (String) request.getParameter("j_captcha_response");
[code]....
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Oct 12, 2014
Scanner sc = new Scanner(System.in);
Question question = new Question();
Quiz quiz = new Quiz();
System.out.print("Enter the prompt: ");
question.prompt = sc.nextLine();
[Code] .....
Here is the example run that I am trying to achieve:
* 1. Enter the prompt: What is the capital of the USA?
* 2. Enter a possible answer: New York City, NY
* 2. Is New York City, NY the correct answer (y/n)? n
* 3. Enter a possible answer: Pittsburgh, PA
* 3. Is Pittsburgh, PA the correct answer (y/n)? n
* 4. Enter a possible answer: Washington, DC
* 4. Is Washington, DC the correct answer (y/n)? y
* 5. Enter a possible answer: Chicago, IL
* 5. Is Chicago, IL the correct answer (y/n)? n
The problem is that my for loop runs through correctly the first time, but doesn't seem to react to me initializing my choices array after that. It ends up looking like this:
Enter the prompt: What is the capitol of the USA?
Enter a possible answer: New York City, NY
Is New York City, NY the correct answer (y/n)?n
Enter a possible answer: Is the correct answer (y/n)?
But I cannot understand why it's doing that.
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Sep 18, 2014
For basic arrays, we can directly combine declaration and initialization as E.g: int[] num= new int[2]
But can we do this do for forming class object arrays? like
class stu
{
.....
}
stu[] s=new stu[2]
????
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Oct 23, 2014
I have a C struct as follows:
struct myHAI
{
int id;
char celcius[5];
char fahrenheit[5];
[Code] .....
I think the Java code is just a little to kludgey. I have to add 256 records to the 3D array which means I have to call the method 256 times. I'd really like to initialize the class all at once similar to the C struct. But I don't know if that is possible. Thus, any less kludgey way of initializing a 3D array?
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Nov 3, 2014
I am writing a program with different screens. At first you have to log in to access the program. So I have a problem with the variables username and password. I can't seem to get theme from the DbConnection class. I suppose it is a basic problem?
In the DbConnection class i have a problem with the returns.
In the Login class i have a problem with the connection.getUsername(); and connection.getPassword();
Here is some code:
class DbConnection
package kim.contracts.database;
import java.sql.*;
public class DbConnection {
private Connection conn;
private Statement st;
private ResultSet rs;
[Code] .....
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Jan 2, 2014
So, I am learning Swing, and Swing Layouts. I just came across a really confusing (for me) line of code.
Java Code:
setLayout(new BorderLayout()); mh_sh_highlight_all('java');
So, this is weird for me because I don't really understand why the BorderLayout class constructor is being initialized as a parameter for the setLayout..
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Nov 15, 2014
i know that int [][] x = new int[2][2] will generate a 2x2 array but I'm looking at a certification mock question and I see double [][] da = new double [3][]. What is the empty [] on the right hand side of the equal sign trying to tell me? Is there some default value?
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Oct 30, 2014
public class Check2
{
private int red;
private int green;
private int blue;
public Check2(){
red = 0;
green = 0;
blue = 0;
[Code] .....
And when i uses it in another class named "Check" it returns zeroes :
public class Check
{
public static void main(String[] args) {
Check2 obj = new Check2(125,254,12); // the toString method should return the values i gave it here . but it shows me zeroes instead.
System.out.println("the colors are " + obj.toString());
}
}
Output : the colors are (0,0,0)
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Feb 7, 2015
I need to pass user input from the main method, which is then validated using another method that is returned as a valid score, and then I pass the valid input to another method that stores the data in an array. The array is initialized within the method. I tried to use an if-else statement to initialize the array, because I originally did this at the beginning of the method. I soon learned that I was creating a new array everything I accessed the method. Needless to say, this isn't working either.
public static void main(String[] args) {
int judges = 7;
float[] validScores = new float[judges];
for (int i = 0; i < judges; i++) {
float score = -1;
[Code] ....
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Mar 19, 2014
Is it possible to write a program that changes the value of a certain variable when a certain predefined time arrives, without running the same loop over and over again (and stucking the computer)?
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Aug 18, 2014
Write a program to initialize and display variable size array.
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Sep 23, 2014
I don't understand how i'm supposed to define a variable when the user has to type it into the program so it can be converted. This program i'm working on is supposed to convert from meters to feet (meter = feet * 0.305) but the user has to type in the meters they want converted. how do i solve the problem that keeps coming up that says "variable meter symbol cant be found" ? I keep trying different lines to no avail
public class Lab2
{
public static void main(String[] args) {
double feet = meter * 0.305;
double meter = feet/0.305;
System.out.println("Enter in feet for conversion to meters");
meter = meter * 0.305;
[Code] .....
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May 21, 2014
Given the case I have an object which is assigned only once. What is the difference in doing:
public class MyClass {
private MyObj obj = new MyObj("Hello world");
private MyClass(){}
//...
}
and
public class MyClass {
private MyObj obj;
private MyClass(){
obj = new MyObj("Hello world");
}
//...
}
Is there a difference in performance or usability? (Given also the case there are no static calls expected) ....
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Oct 27, 2014
The term "Local variable" is related to scope. That is a local variable is one which is defined in a certain block of code, and its scope is confined inside that block of code.And a "Member variable" is simple an instance variable.
I read in a discussion forum that when local variables are declared (example code below), their name reservation takes place in memory but they are not automatically initialized to anything. On the other hand, when member variables are declared, they are automatically initialized to null by default.
Java Code: public void myFunction () {
int [] myInt; // A local, member variable (because "static" keyword is not there) declared
} mh_sh_highlight_all('java');
So it seems that they are comparing local variables and member variables. While I think a member variable can also be be local in a block of code, isn't it?
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Jan 11, 2015
Given a reference variable : Car c1 = new Car();
when we create another variable and set it equal to the first : Car c2 = c1;
we're pointing c2 at the same car object that c1 points to (as opposed to pointing c2 at c1, which in turn points at the car). So if we have code like,
Car c1 = new Car();
Car[] cA = {c1, c1, c1, c1};
are we doing the same? Are we creating four *new* reference variables, each of which points at the same car (again as opposed to pointing them at c1 itself)? I think so, but want to make sure I'm understanding this correctly.
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May 23, 2014
I have a JFrame jf and JPanel jp on it. jp has five TextFields named cel1, cel2.. cel5. I wish to construct a String Cel + for loop index and run a for loop to reset the values of all the text fields using a single statement such as cel1.SetText("abc"). Similar things can be done in foxfro. How does one do it in java?
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Feb 17, 2014
How do I use a variable in an if statement to return a public void method from another class? I've tried:
System.out.print("select 1 - 6: ");
Scanner myScanner = new Scanner(System.in);
myScanner.nextInt();
if (myScanner.nextInt()==1) {
carSelection colour = new carSelection();
colour.carSelection();
The method colour in class car selection is just 4 print line statements? I've // out the if statement to see if it is correctly calling the method and displaying the data and it is?
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Oct 6, 2014
What is variable shadowing?When does it occur?
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Feb 7, 2014
Regarding the code examples in Head First Java, this is from Chapter 5, regarding the beginning creation of the dot com game. There are two classes in quesiton
the first is the SimpleDotComTester class:
public class SimpleDotComTester {
public static void main(String[] args)
{
SimpleDotCom dot = new SimpleDotCom();
int[] locations = {2, 3, 4};
dot.setLocationCells(locations);
String userGuess = "2";
String result = dot.checkYourself(userGuess);
}
}
and the second one is the code for the checkYourself () method in the SimpleDotCom class
public class SimpleDotCom {
int[] locationCells;
int numOfHits = 0;
public void setLocationCells(int[] locs)
[code]....
Now I noticed that both classes use a variable called result; the program runs fine, but assume from the example that you can use the same variable name two different classes;
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Mar 16, 2014
i have a datatable with id= tblId#{emp.id}
<c:set var="tableID" value="tblId#{emp.id}">
displaying employee details inside c:forEach
closing dataTable.
[code]...
For ex.Displaying 5 table dynamically.Need to validate check box selected or not.5 table are displayed.But it shows 5th table row id only.It is because of local varible declaration?
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Nov 6, 2014
I'm making a program where the user enters an ID number and can submit the amount of sales that person made for a specific product and write to a file. One of the things I have to do is making a running sum of the sales for each product for all people combined as well as an accumulation of the a persons sales every time he enters data. Everything seems to be working execpt my values like person1Total, person2Total...etx and product2Total.
When I try to write them to the file, they always come out at 0.0 even though they should be the sum of the indexes of the array sales.
import java.io.*;
import java.util.Scanner;
public class SalesReport {
// private static double p1Total, p2Total, p3Total, p4Total;
private static double product1Total, product2Total, product3Total, product4Total, product5Total;
private static double person1Total, person2Total, person3Total, person4Total;
public static void main(String[] args) throws IOException
[code]....
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May 2, 2015
I'm working on a program where the user inputs song information (name, artist, filesize, duration) which is stored in a database. Once the user adds a song, the details should be stored in the first empty song slot (4 song slots total) and then taken back to the menu interface.
What I'm having trouble with is that I can add the first song fine (song1), but when I try to add another song, the information entered into song1 is gone. I've worked out that this is because every time I call upon the addNewSong() method, I'm creating four Song objects that are brand new with the line:
Song song1 = new Song();
Song song2 = new Song();
Song song3 = new Song();
Song song4 = new Song();
How to fix this problem is where I'm stuck because if I move these lines elsewhere, I get a 'cannot find symbol - variable song1' error.
Here is my code:
public class SongDatabase {
Scanner console = new Scanner(System.in);
public void addNewSong() {
Song song1 = new Song();
Song song2 = new Song();
Song song3 = new Song();
Song song4 = new Song();
if (song1.isEmpty()) {
[code]....
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Jul 18, 2014
I trying to display the value of a variable from a method, but I don't know why it will I can't do it.
//Java extension package
import javax.swing.JOptionPane;
public class Palindrome
{
public static void main(String[] args) {
int number = 0;
int palindrome = 0;
[Code] ....
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Oct 24, 2014
I have code that displays 3 game scores the series total and average. For some reason game 3 outputs 0 and game 1 and 2 output correctly. I don't see anything different that game 3 is doing that game 1 and game 2 aren't so I'm not sure what the problem is.
java file
package com.valenciaprogrammers.mybowlingscores;
import java.text.DateFormat;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Date;
public class BowlingScores implements Comparable<BowlingScores>{
private long id;
[Code] .....
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