JTextField That Accept Only Integer Input?
Jul 5, 2014
I have a GUI with a JTextField. I need to check that the input entered by the user is made up of only integers.
For example I accept: 1, 10, 530, ...
I do not accept: -10, 1.5, -6 ...
I would like to implement this control by using a regular expression so I would have a code like that.
JTextField text = new JTextField();
String input = text.getText();
boolean bool = checkInteger(input);
if(bool)
System.out.println("Ok");
else
System.out.println("Error");
The checkInteger(String input) method should check if the input string is correct or not.
How can I do to implement this control with regular expressions?
Is there an easier way to do it?
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Apr 14, 2014
This program is supposed to accept an integer as an input and display the message that the number is even or odd. The main method calls a Boolean method. Write a method private static boolean iseven(int number and the message is printed from the Main method. This is what I have.
import java.util.Scanner;
public class OddorEven {
int number;
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
[Code] ....
I know the message is not being printed from the Main method. I'm not sure how to do that.
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Jan 28, 2015
I am attempting to write a program that accepts input of a positive integer, reports each digit and then the sum of all digits. This is what I have so far:
*/
package numbersum;
import java.util.*;
public class Week4NumberSum {
static Scanner console = new Scanner(System.in);
/**
* @param args the command line arguments
[Code]...
It works if I enter 1234567891 (10 digits)
Enter a positive integer: 1234567891
digit: 1
digit: 2
digit: 3
digit: 4
digit: 5
digit: 6
digit: 7
digit: 8
digit: 9
digit: 1
The sum of the digits is 46
But if I enter 11 digits, it fails:
Enter a positive integer: 123456789123 (12)
Exception in thread "main" java.util.InputMismatchException: For input string: "123456789123"
at java.util.Scanner.nextInt(Scanner.java:2123)
at java.util.Scanner.nextInt(Scanner.java:2076)
at week4numbersum.Week4NumberSum.main(Week4NumberSum. java:26)
java - Scanner error with nextInt() - Stack Overflow gives me some infor for InputMismatchException - which I find described as In order to deal with this exception you must verify that the input data of your application meet its specification. When this error is thrown, the format of the input data is incorrect and thus, you must fix it, in order for your application to proceed its execution.
I don't understand why the 10 digit integer is OK but the 11 or > digit integer is a mismatch.
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May 22, 2015
Write a function that accepts an array of non-negative integers and returns the second largest integer in the array.
Return -1 if there is no second largest.
The signature of the function is int f(int[ ] a)
Examples:
if the input array isreturn{1, 2, 3, 4}3{{4, 1, 2, 3}}3{1, 1, 2, 2}1{1, 1}-1{1}-1{}-1
In the signature what I understood is, I should write my function with the given signature,
The return type is "int"
method name is "f"
parameter is "a" right ?
Writing my doubts beside the particular line in the code
public static void main() // In the answer why they didn't use the class ?
In main method why they didn't use parameters ?(String[] args)
{
a1(new int[]{1, 2, 3, 4}); // what is "a1" here is it array name ? this line initializing the array ?
a1(new int[]{4, 1, 2, 3});
a1(new int[]{1, 1, 2, 2});
a1(new int[]{1, 1});
a1(new int[]{1});
a1(new int[]{});
}
static int a1(int[] a) // what is "a" here parameter ? and "a1" is method name ? why they used the array name and method name same ?
{
int max1 = -1;
int max2 = -1;
for (int i=0; i<a.length; i++)
[Code] .....
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Nov 1, 2014
I am practicing some basic recursion and I was trying to solve this problem
Write a method sumTo that accepts an integer parameter n and returns the sum of the first n reciprocals. In other words:
sumTo(n) returns: 1 + 1/2 + 1/3 + 1/4 + ... + 1/n
For example, the call of sumTo(2) should return 1.5. The method should return 0.0 if passed the value 0 and should throw an IllegalArgumentException if passed a value less than 0.
This is my attempt to do it , however my output is always a 0.0 , and i do not understand why :
public static double sumTo(int n ){
if(n<0){
throw new IllegalArgumentException();
}
else if (n==0){
return 0.0;
[Code] .....
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Feb 8, 2015
Write a java program to accept a string, float and an integer as command line arguments. String value should be displayed. Also the program should display the maximum value of two numbers. Use Integer.parseInt() and Float.parseFloat()
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Nov 20, 2014
Write a method maxOccurrences that accepts a list of integers as a parameter and returns the number of times the most frequently occurring integer (the “mode”) occurs in the list. Solve this problem using a map as auxiliary storage.
If the list is empty, return 0.
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Jan 14, 2015
I am trying to create a fortune teller and everything is running fine except the program does not prompt you to answer the questions
Do you like donuts?
and
What did you have for breakfast?
Here is the code this is in Bluej :
import java.util.Scanner;
public class FortuneTeller {
public static void main(String[] args) {
Scanner keyboard = new Scanner(System.in);
System.out.println("Welcome to Fortune Teller");
[Code] .....
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Nov 8, 2014
How can I get enter(return) as empty input from user?!
scanner.next will wait until I input a string ...
But I want it when I hit return sets the variable to empty string ...
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Mar 13, 2015
I want to write a program that accepts user input and then prints its average in a serial way.
Suppose i enter 5. I should get result 5 first time then i input 10 then it should return the average of (5 and 10) and then i enter say 20 it should return average of (5,10 and 20) and so on.
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Jun 29, 2014
How would I display certain output text if the text entered equaled "text".
So lets say you enter a question into a JTextField. You press a button that submits the text. The output displayed depends on what the question you asked was.
Think about it as "If question = What color is the sky? On submit, display text "Blue". How to implement this.
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Sep 13, 2014
I need to get users input from jtextfield and set it to JTable. This is my code:
public class Projektni extends JFrame {
public final JTextField ime = new JTextField(10);
public final JTextField prezime = new JTextField(10);
public final JTextField index = new JTextField(10);
public DefaultListModel podaci = new DefaultListModel();
JButton imeB=new JButton("Upisi u tabelu");
[Code] ....
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Oct 21, 2014
I'm trying to get data from a GUI input window into an ArrayList and back out via a JTable. I can get the array lists to print to the console within the input class, but I need to wire it to a data container and out through a different class. Here is code from one input class, and its corresponding output class:
Input:
public class AddClassroom extends JFrame implements java.awt.event.ActionListener {
// UI components
// are declared here...
[code]....
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Sep 7, 2014
I am having trouble taking user input and passing it to another class as a variable. If I assign the value explicitly (see line 59), it works just fine. What I want to do though, is assign the input from inputField to the variable inputVariable. I tried using:
inputVariable = inputField.getText();
This does not work. Regardless of what is typed into inputField, the output I get is just:
"The user typed "
package example;
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
[Code] .....
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Dec 4, 2014
I am trying to populate a JTable using Several JTextFeild a JComboBox and a JLabel.
The textfields are originalPrice and itemName
JComboBox is departmentComboBox
label is salePriceLable.
When hitting the button i need the program to calculate the price after discount and add the item name, department, original price, and discounted price to a table. I have the calculation down, but am lost on populating the table.I used NetBeans 8.2
/*
* Program: JavaRetailCalculator
* Purpose: To calculate the ammount of a discount and display results in a Table
*/
import java.awt.*;
import javax.swing.*;
public class CalculatorFrame extends javax.swing.JFrame {
/**
* Creates new form CalculatorFrame
*/
public CalculatorFrame() {
initComponents();
[Code] .....
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Sep 13, 2014
I have project to get from users input like name,surname,to save to Jtable,i have table and jtextfiled but when user get input they don t save to table here is my code:
Project.zip (33.54K)
public class Projektni extends JFrame {
public final JTextField ime = new JTextField(10);
public final JTextField prezime = new JTextField(10);
public final JTextField index = new JTextField(10);
public DefaultListModel podaci = new DefaultListModel();
public JList lista = new JList(podaci);
String kolone[] = {"ID","Name","Age"};
[Code] ....
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Sep 16, 2014
I am required to read user input to create two matrices which will eventually be added together. I am unsure as to how I can read the input from the user as an int and not a String. The input is from size 0-10 for both column and row size. Also, can you have a new button created in the actionPerformed method of a previous button?
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
public class Matrices implements ActionListener {
private JFrame win1, win2, win3, win4;
[Code]...
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Jan 29, 2014
I have been creating a Java program to track inventory using an array. I need to add a search function to it to take a term, input through a text field, and locate a matching instance within the array. How can I code a JButton to grab test input from a JTextField and search for it within the array then display the corresponding information? I also need to add buttons to add and delete items as well.
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Dec 18, 2014
I have to ask how many children's tickets you want to order. When I apply the code below, it just accepts whatever I input, including letters. I imagine it is to do with setting childrensTickets = 0? If I input a letter using the below it accepts - shouldn't it print the error given the input is not >=0?
System.out.print("How many children's tickets do you require? ");
int childrensTickets = 0;
boolean validChildrenValue = false;
while (validChildrenValue == false) {
if(aScanner.hasNextInt()) {
[Code] ....
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Jul 21, 2014
I have a program in which I take some characters input from User
using
String inputString=in.next();
How can i restrict user that input should be only char 0 or 1?
If the answer is regular expressions then What Should be Its Regular expressions?
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Jun 12, 2014
So I clipped this out of my Jeopardy game code and made it into its own project for testing. using this code I want to check to see if the input for wage is an integer?
import java.util.Scanner;
public class test {
/**
* @param args
*/
public static void main(String[] args)
{
Scanner input = new Scanner (System.in);
Obviously right now if you enter "aflwkj" or some such for the wager, the program terminates. How to make a loop that will keep asking the user for a value for wage until the input is an integer?
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Dec 18, 2014
System.out.print("To begin, please enter 1 to choose stand tickets or 2 to choose terrace tickets for your party. ");
int standOrTerraceTickets = aScanner.nextInt();
while (standOrTerraceTickets != 1 && standOrTerraceTickets != 2)
{
System.out.print("Invalid input. Please enter 1 for stand tickets or 2 for terrace tickets. ");
standOrTerraceTickets = aScanner.nextInt();
}
Okay I thought I had this working properly so that when the user entered anything other than 1 or 2 they would keep getting an error invalid input, however, that only works when the user enters an integer. If the user enters anything other than a number, the program crashes. How does one prevent this from happening?
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Sep 7, 2014
I am new to java and programming in general. I figured out how to convert an integer input to binary however I am having issues doing the opposite of converting a user input binary number to a decimal.
I need to do this with basic math (or string depending on how I represent the binary) and no functions.
I know how to convert binary to integer on paper but I am having a hard time working it out in java.
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Feb 8, 2014
I want to limit the program to only accept a 12 digit input and an integer value but I don't know how to program it,
import java.util.Scanner;
public class testing4
{
public static void main(String []args) {
Scanner reader = new Scanner(System.in);
String input;
[Code]...
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Apr 21, 2015
I have to write a program that inputs a 5 digit integer from the keyboard and prints if the input number is a palindrome or not. I got it to work, but when my result prints it says "0 is a palindrome" or "0 is not a palindrome". How can I get rid of the 0 and replace it with the number input by the user?
import java.util.Scanner;
public class Palindrome {
public static void main(String[] args) {
int number;
int digit;
int temp;
[code]....
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Mar 18, 2015
I am trying to create a program that first asks the user for an input in the form: condition = value, where condition is a word from the set {limit, deficient, abundant, perfect, prime}, and value is a positive integer. Then it verifies the input. If the input is invalid it prints a message indicating that and terminates. If the input is valid it prints a table with the number of abundant, deficient, perfect and prime numbers less than or equal to N, where N = 1, 2, 3, ..., limit.
My problem is with the input validation. i want it to read the value as a string and verify if it's integer.
Here is my code
import java.util.Scanner;
public class Factors
{
public static void main (String[] args)
{
Scanner scan = new Scanner(System.in);
int n, f, fsum, p=0, a=0, d=0,pe=0,limit=0,abundant=0, deficient=0;
System.out.print("Enter stoping condition (condition = value): ");
String cond = scan.next();
[Code] ....
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