I have a project for a class where I'm supposed to be something with private arrays and private integers and I still don't understand the point of private anything within java. if I want to change a variable I'll change it. if I want it to stay the same I'll leave it the same. so what point is all this private/public nonsense unless I'm trying to stop hackers or something?
View RepliesI am just learning arrays or rather teaching myself about them and I am not to sure how they work and why. I understand that in order to set one up you do
int[] example1;
example1 = new int[]{01, 02, 03, 04};
But I don't really understand is why if you only need 3 data integers, why put the 4th one in?
Also with outputting data, I understand .print() and .println() but I am not to sure what .printf() does and then the formatting after that.
System.out.printf("%3d%11") // and then what you want to print
I am doing an assignment for a college class. We are asked to get user input and decide if it is a valid IP address and then check what class the address is and if it is a public or private address.
So far, I can get the input, and check to see if the numbers are in a valid range. I can also display the IP address to the user. I am having an issue figuring out how to get the program to check the classes and whether they are public or private.
import javax.swing.JOptionPane;
/**
This program will take user input and calculate whether it is a valid IP address and the class that it belongs to.
*/
public class shortONE_1
{
public static void main(String[] args)
{
//Variables
final int MIN_OC = 1; //Minimum number accepted
final int MAX_OC = 255; //Maximum number accepted
final int MIN_A = 1; //Min number for class A
final int MAX_A = 127; //Max number for class A
[Code] ....
Design, write a java program to input 7 integers and, for each integer, calculate and display its square and cube.
View Replies View RelatedI wrote this simple piece of code to find the number in the given array of Integers. The program works fine although it shows a couple of errors when i modify it a little bit.
public class DemoLabel{
public static void main(String [] args){
int[][] arrofInts={
{32,45,67,87},
{23,44,55,66},
{12,47,87,56},
{23,44,12,78}
[Code] .....
In the disp() method,Suppose i only want to pass two arguments i.e disp(i,j) given that searchFor variable is visible in the entire class but when i use disp(i,j) i get the following error
DemoLabel.java:38: error: cannot find symbol System.out.println("The number "+searchFor+" is at the location"+i+" , "+j);
^
symbol: variable searchFor
location: class DemoLabel
So i decided to declare the
int searchFor
as
public int searchFor
But the compiler threw another error saying that it was a Illegal start of expression
Also,when i add a SOP line after the label search: it shows the error
DemoLabel.java:25: error: undefined label: search
continue search;
^
Although i got the program to work it would be useful if i could understand why it doesn't work with the modifications.
Project is due before midnight eastern time (3 more hours). I have been working on this all day, we have not learned arrays or anything and just started 'for' loops. I don't really know how to implement that system yet. However, he wants us to check all the possible handwritten math ways of doing this. I have tried but I cannot return my numbers beside the card.my program only prints the type and I still have more cases to add as well..
QUESTION: Write a Java program that reads 5 integers, each of which is in the range of 1 and 13 representing a simplified poker card with no suit. Your program should then print the ranking of the hand with card number(s) beside the ranking. The rankings to determine are Four of a Kind(4 of the 5 cards of the same rank), Full House(3 of the 5 cards of the same rank, and 2 cards of another rank), Straight(5 cards of sequential rank), Three of a Kind(only 3 cards of the same rank), Two Pair(2 cards of the same rank, 2 cards of another rank, and no card of either rank), One Pair(only 2 of 5 cards are of the same rank), and High Card(no two cards of the same rank). Some sample runs are:
input: 2, 3, 2, 2, 2; output: Four of a Kind(2)
input: 2, 3, 2, 3, 2; output: Full House(2, 3)
input: 2, 3, 4, 5, 1; output: Straight(5)
input: 1, 13, 11, 10, 12; output: Straight(1)
[code]....
I don't want to use an array. I do not know of a function built into Java to allow me to do this.
View Replies View RelatedHow do I code this without having the need to use iterator? Code a Java method that accepts an ArrayList of integers and an integer. The method should delete all elements in the array list exactly divisible by the integer and return the number of remaining elements.
View Replies View RelatedI mainly would like to know is a int[4][4] or a int [4*4] is more efficient to use. Which takes more storage? Which requires more to process? that kind of stuff.
View Replies View RelatedSo like, in lua programming language you can do things like,
Array = {1, 2, 3, abc = 5, efg = {123, 456, 789, hij = {"tests","works!"}}, hij = true}
Array[1] = 5
Array[3] = true
Can you do atleast something like this in java or?
I would like to do this because if let's say I was making a game, I could define what tiles are passable and which are not and then their location or something, so like this:
//p (passable) stands for if possible to walk on
//c stands for tile image
t = ["grass.png","water.png","chest.png"]
Tiles = [
[p = false, c = t[1], x = 3, y = -2 ],
[p = true, c = t[0], x = 4, y = 3 ],
[Code] ....
Or something...
I have to write a program that takes an array of grades and calculate the average and then count the number of grades that are above average and also count the number of grades that are below average. This is what I have so far, it calculate the average and tells me how many are above average... where and how do I get to count how many are below average
public class arrays{
public static void main(String[] args) {
final int grades = 5;
double[] numbers = new double[grades];
double sum = 0;
[Code] .....
I am trying to do this assignment but I can't get the needed output. Create a program that asks the user how many floating point numbers he wants to give. After this the program asks the numbers, stores them in an array and prints the contents of the array in reverse order.
Program is written to a class called ReverseNumbers.
Example output
How many floating point numbers do you want to type: 5
Type in 1. number: 5,4
Type in 2. number: 6
Type in 3. number: 7,2
Type in 4. number: -5
Type in 5. number: 2
Given numbers in reverse order:
2.0
-5.0
7.2
6.0
5.4
My code:
import java.util.Scanner;
public class apples {
public static void main(String[] args) {
Scanner reader = new Scanner(System.in);
double[] numbers;
System.out.print("How many floating point numbers do you want to type: ");
[Code] .....
This is my code.
public class PA9 {
public static void main(String[] args) throws FileNotFoundException {
// create data file to read from
File inf = new File("cityPopulationData.txt");
//Create a file to write out to.
PrintWriter fileOut = new PrintWriter("output.txt");
[Code] .....
This is my error
Exception in thread "main" java.util.InputMismatchException
at java.util.Scanner.throwFor(Scanner.java:909)
at java.util.Scanner.next(Scanner.java:1530)
at java.util.Scanner.nextInt(Scanner.java:2160)
at java.util.Scanner.nextInt(Scanner.java:2119)
at PA9.getData(PA9.java:35)
at PA9.main(PA9.java:22)
Write a Java program to read from the data file, find the city with the highest population based on the 2010 census data, the city with the highest population growth from 2010 to 2013, the city with the lowest population growth from 2010 to 2013, and the city with the highest density (number of persons per sq. mile).
import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.Scanner;
[code]....
I am trying to write a code that allows you to input 2 lists and it tells you if they are identical or not. However, when I enter my fist list I can only enter two values and then it asks for the next list. How would I fix this to allow me to enter more than two values?
Also, If the second list is different it has me enter more values that list one.
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
// Enter values for list1
System.out.print("Enter list1: ");
int size1 = input.nextInt();
int[] list1 = new int[size1];
for (int i = 0; i < list1.length; i++)
list1[i] = input.nextInt();
// Enter values for list2
System.out.print("Enter list 2: ");
[code]...
My output looks like this:
Enter list1: 1
2
Enter list 2: 2
3
2
Two lists are not identical
I am having some trouble with a Java program. I have a txt data file, which I will display, that I need to add into two separate arrays. The text file is 8 lines long that is supposed to go into two separate 4x4 matrices. A little background info on this program, reads in two arrays, compares them and outputs the largest elements of the same index and outputs them in a separate array. I somehow cannot seem to figure out how to do this. My code is below:
Data File:
2 7 6 4
6 1 2 4
9 7 2 6
8 3 2 1
4 1 3 7
6 2 3 8
7 2 2 4
4 2 3 1
Code:
public class prog465a {
public static void main(String[] args) {
Scanner inFile = null;
try {
inFile = new Scanner(new File("prog465a.dat.txt"));
[Code] .....
Recently I have missed a few weeks of my class due to family emergencies. Because of this I have missed very important lectures. My professor has assigned me the following assignment:
Prices Write a Java program that specifies three one-dimensional arrays names price, amount, and total. Each array should be capable of holding 10 elements. Using a loop, input values for the price and amount arrays. The entries in the total array should be the product of the corresponding values in the price and amount arrays. After all the data have been entered, display the following output:
Total Price Amount
==== ==== ======
Under each column heading display the appropriate value.
I know how to display everything using printf, how to create the actual arrays and define the array size, but I am confused on how and what loop to use and how to construct it. This is what I have managed to write up so far:
import java.util.Scanner; // Imports the Scanner class
import java.text.DecimalFormat; // Imports the DecimalFormat class
public class Prices
{
public static void main(String [] args)
{
double[] price = new double[10];
double[] amount = new double[10];
double[] total = new double[10];
// Create a new Scanner object
Scanner keyboard = new Scanner(System.in);
} //End of main method
} // End of public class
So I'd like to know what all the statement, not sure if it's the correct way of calling them but I'd like to know what like all of those purple-ish colored words in eclipse actually mean.Here's what I know so far, so if you can add some stuff to it or just correct me:
public - can be accessed by different classes.
private - can't be accessed by different classes.
static - adds a '.' which pretty much lets you like use methods on it? Not really sure about this one.
final - a final value of a variable meaning it couldn't and willn't change?
super - I have no clue, maybe something that has to be executed first? Not sure.
void - bassicly you don't have to use return as it doesn't return any value.
this - Uh-.. I think it has something to do with the class this keyword has been entered into, not quite sure what it does though.
I assume there are alot more but I am just not sure about these common ones, what the actually do and what's their purpose?
What happened when we use main() as a private. . . . .???????
View Replies View RelatedI am creating a slot machine using eclipse. I am trying to get the "winnings" JTextField to be updated in a way so that when the random images have been selected it adds to the number that is already displayed in the JTextField as opposed to what it is doing at the minute which is just displaying how much was won on that particular spin. I am also struggling to set a code for when noting is won, nothing is added. My code is below.
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
import java.util.*;
import javax.swing.Timer;
[Code] ....
It isn't messing up it just keeps making me make my arraylist static and i'm not sure why.
public class driver
{
private static ArrayList<AddItems> items;
public driver()
[Code]....
I'm working on a project that contains multiple classes. Each class contains and must contain only PRIVATE variables. Here's my issue. When my test code calls for a new instance of "StudentClass" as so:
StudentClass studentClass = new StudentClass(offeredClass.getClassIdNumber(),
offeredClass.getClassName(),
offeredClass.getClassroom());
The corresponding constructor won't let me initialize it's variables because they are declared private within another class, as shown here:
StudentClass (float classIdNumber, String className, Classroom room){
this.classIdNumber = classIdNumber;
this.className = className;
this.room = room;
}
When getClassName, getClassroom, and getClassIdNumber are passed to a toString() method elsewhere in my test code. the output is returned just fine. When passed through the StudentClass, I'm getting Null across the board.
The first is clear , new Person().printPerson(); displays Person but for the second : new Student().printPerson(); it accesses the Student constructor that points to the Person class => object. It builds the Person instance then goes back to the Student constuctor .Both methods are private and to my knowledge invisible one to the other , except that you cant run the the Person one because it's private so the only one in the Student class is the Student one . Guess it 's incorrect , but why ? (is because private methods cant be overriden and somehow the super class one always has priority ? , even if it's private?)
public class Test {
public static void main(String[] args) {
new Person().printPerson();
new Student().printPerson();
[code]....
public class StudentNumber {
/*
public StudentNumber(){
System.out.println("test");
}
*/
private char c='W';
public StudentNumber(float i){
System.out.println(i);
[Code] ....
Exception in thread "main" java.lang.RuntimeException: Uncompilable source code - c has private access in extention.pkgsuper.StudentNumber
at extention.pkgsuper.ExtentionSuper.main
I did cast type. So what's the problem?
Java Code:
import java.util.Scanner;
import java.util.ArrayList;
public class Problem1
{
public static void main(String[] args) {
Scanner scan = new Scanner(System.in);
ArrayList<String> list = new ArrayList<String>();
[Code] ....
There is an error and says that my ArrayList has private access. I can't figure out how to fix it.
The code runs but when I enter "Quit", the program just stops. The arraylist isn't printed out?
When creating a class with a constructor, why does one have to create private variables (attributes) to be used as parameters by the object? The object's parameters will be set to be exactly equal to the private variables (attributes), so what is the point of having the private variables (attributes) Why are both private variables (attributes) and parameters needed when they are set to be equal each other anyway?
View Replies View Related