I am trying to calculate factorials using BlueJ. All of my factorials calculate correctly, I am just having an issue with something the instructor asked of us. She asked us to force the loop to stop when the user inputs "Calculate the factorial of 0", and not give any print.
So far I have my for loop with the correct conditions, I am just really confused as to how to make an if statement to stop the code when the input is 0.
The first method returns the factorial of an integer (factorial of 3 = 1x2x3). And the second returns the sum of the factorials between 2 integers. This is correct according to my professor. I'm just confused as to why in the 2nd methods it isn't "total = total + Factorial(i);" instead of what I have.
public class LoopProblems
{
public int Factorial (int n){
int total = 1;
for (int i = 1; i <= n ; i++ ) {
total = total * i;
}
return total;
}
public int SumOfFactorials (int start, int end) {
[code]....
I have to write a program that computes factorials up to 50
public static void main(String[] args) {
int [] a= new int [100];
for(int n=0; n<=50; n++) {
double factorial = 1;
for (int multiplier=1; multiplier<=50; multiplier++)
[Code] ....
I have this as my code so far I just don't know how to incorporate the array in there which i need to do as well as I dont get why all the output comes out for every single thing . IT will write 1 factorial and display all the factorials up to 50 and do the same pattern over and over again.
I have written the following code to try and find a factorian but it doesn't work all the time. A factorian is supposed to be the sum of the factorials.
public static boolean isFactorion(int n){
boolean rv = false;
int sum =0;
int fact = 1;
for(int i = n;i>=1;i--){
fact = fact * i;
[Code] ......
I'm trying to write a program that calculates the factorials of the numbers 1 through 10, based on user input... My problem is that I don't know how to address the possibility of the user entering something other than a number. When I test the following code by entering a letter, I get an Input Mismatch exception. I'd like to be able to inform the user that the entry is invalid, and ask for another response. Here is my program thus far:
Java Code:
import java.util.Scanner;
public class Factorial {
public static String entryString;
public static char entryChar;
public static Scanner input = new Scanner(System.in);
[Code] ....
I am new to BlueJ. I have to add Javadocs every time I finish the program, but I see a folder named "doc" .
What's that folder ? Is it Javadocs?
I see :ToolsProject Documentation => regenerate??
i have a problem, i need build a calender in BlueJ. The program need to found if I put this one year have to give me the full schedule but only the first semester.
View Replies View Relatedthe system I am using is blue jay and java. my problem is that I have this error message pop up whenever I try to compile any of my 6 classes. Three of the classes are cities, 3 others are shops, and the final one is a inventory called Player. The following is the error code that appears when I try to compile class THshopB or class CityB.
method run in class CityB cannot be applied to given types;required: Player; found: no arguments; reason: actual and formal argument lists differ in length
A similar error occurs for the rest of my City and THshop classes,except it replaces the class CityB with CityA and occurs in class THshopA, replaces CityB with CityC when occurring in class THshopC.The public methods of CityB and THshopB are shown below, as I believe that something is wrong with the public method of one or the other. I have the code [CItyB.run();}] inside of class THshopB, and run is the part that gets the red highlight error described above.THshopB public method
[ public static void shop(Player inventory){
CityB.run();}]
CityB public method
[ public static void run(Player inventory){
THshopB.shop(inventory);]
All of my THshop classes are written in the same format, and all of my City classes are written in the same format,
I typed the following program using BlueJ
import static java.lang.System.out;
import java.util.Scanner;
import javax.swing.JFrame;
public class Main {
public static void main (String args[]) {
Scanner read = new Scanner (System.in);
out.print ("> ");
double num = read.nextDouble();
out.println (num);
}
}
When I compile the code it gives me no errors; however when I run the program and write a floating point number it gives me the following message:
java.util.InputMismatchException: null (in java.util.Scanner)
I used to use an online compiler and the nextDouble() method worked perfectly there.
I've been doing a course with a heavy focus on applets and AWT using BlueJ. I've branched out and learn to convert my applets to applications. I can successfully use frames to do similar things to applets (in BlueJ's applet viewer) but I can not seem to run more than application at a time (unlike applets where I could run several at the same time).
Below is a simple Hello World program I wrote. When I re-run main() it closes the original and starts again. (I'm aiming to explore the java.net.* libraries and for testing would like to use more than one frame at a time which can communicate to each over via sockets).
import java.awt.*;
import java.awt.event.*;
public class HelloWorld extends Frame implements WindowListener {
public static void main (String[] args) {
HelloWorld app = new HelloWorld();
app.setSize(500,500);
[code]....
I am using blueJ as my java editor.
If I have a method that creates a new variable (the name of which is a string argument for the method). Can I get that variable to appear in the workspace in the variables pane?
So instead of just using return to output the variable how do I get in that variables pane?
I have to mirror an image in BlueJay (java)
I have the following code, but it is missing a little bit. My instructor gave me a hint. He said that i have to use the setValue() and getValue() methods, but i'm still confused..
This code only return a black image with the same compositions as the image I want to mirror.
public Image mirror()
{
Image mirrorImage;
mirrorImage = new Image(foto.getWidth(), foto.getHeight(), "spejling");
for(int i = 0; i < foto.getWidth(); i++)
[Code] ....
I'm trying to generate a multicoloured brick wall as part of an assignment using BlueJ.
According to the instructions we've been given, once the wall is set up and we invoke the draw() method, if we invoke the toggleMultiColoured method the bricks will go from being all read to a mix of 6 different colours...
...When I invoke the toggleMultiColoured method, however, the wall I generate is still red.
Here's the source code for the BrickWall class I wrote:
Java Code:
public class BrickWall
{
private int bWidth;
private int bHeight;
private int numRows;
private int rowLength;
private ArrayList<String> colors;
private ArrayList<Rectangle> bricks;
[Code] .....
Driver:
*initiating theGrid[][]*
public Zhang()
{
con.setLayout(new FlowLayout());
for (int xDimension = 0; xDimension<theGrid.length; xDimension++)
[Code] ....
All I'm getting as a blank screen and I've searched for what to put into object oriented code to make the image show up how to program using 2d arrays. I don't get any error messages (which is good I suppose) but how to make the image show up because I have stuff under the graphics and draw methods, did I do something wrong where initializing the array?
I am coding for the first time using the simplified BlueJ platform. I am trying to write a simple conversion program from cm to inches and inches to cm.
Here is my code so far (I also have the textIO file linked to it):
public class UnitConverter {
public static void main(String[] args){
int inchesTocentimetres, centimetresToinches, exitApplication;
int choice;
double result;
[Code] .....
USING A WHILE OR A DO-WHILE LOOP write a program to compute PI using the following equation:
PI = 3 + 4/(2*3*4) - 4/(4*5*6) + 4/(6*7*8) - 4/(8*9*10) + ...
Allow the user to specify the number of terms (5 terms are shown) to use in the computation. Each time around the loop only one extra term should be added to the estimate for PI.
Alter your solution from part one so that the user is allowed to specify the precision required between 1 and 8 digits (i.e. the number of digits which are correct; e.g. to 5 digits PI is 3.14159), rather than the number of terms. The condition on the loop should be altered so that it continues until the required precision is obtained. Note that you need only submit this second version of the program (assuming you have it working).
I'm trying to calculate sin(x) without using Math.sin(x). The formula for sin(x) is: x - x^3/3! + x^5/5! ... I can't seem to get the coding for the alternating +/- right. Here's my program:
import java.util.Scanner;
import java.lang.Math;
class Sin
{
public static void main(String[] args)
{
Scanner kb = new Scanner(System.in);
int n, c, fact = 1, count = 1;
double x, sum = 0, sum_sin = 0, result;
[Code] ....
I'm working on some exercises and I'm having some problems with a method. I want to create a method to calculate the Factorial of an int number. I already wrote code that asks the user to input an int number and it calculates the Factorial, and it works fine
i.e.: if I input 5 it outputs
5! = 120
as it should. Here's the code:
import java.util.Scanner;
public class Factorial1 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int number;
int total = 1;
[Code] ....
Now I want to make a method to re-use this code in other programs and I wrote this program:
public class TestClass {
public static void main(String[] args) {
System.out.print(factorial(5));
}
public static int factorial(int x) {
int total = 0;
[Code] ....
But when I run this program it outputs 0 instead of 120. What is wrong with this code as it compiles just fine but doesn't work as intended.
I'm struggling with this assignment I was given:
Given list of positive integer values, write a program to calculate average of the values. List terminates with -1.
I am working on the first example in this java game programming book. I am having trouble understanding this basic concept. How does the delta variable work throughout this class? I know the syntax I just don't understand the concept fully.
Explain these components of the program:
1) delta += current-lastTime works
2) lastTime = current;
3) if(delta > 1000)
{
delta-1000
....
}
package javagames.util;
public class FrameRate {
private String frameRate;
private long lastTime;
private long delta;
private int frameCount;
[Code] .....
what I'm missing to calculate the Total Payout that Payroll has given out to two employees. the professor states that we have to use "getTotalPayout" . It would have been easy to do "(employee1.getFinal() + employee2.getFinal())" but he use getTotalPayout.
public class Payroll
{
private String employeeId;
private int hourlyrate, hoursworked;
private int increaseHours = 10;
private double TotalPayout;
[code]....
I am supposed to be doing a class assignment that calculates the area of a triangle and outputs with JOptionPane. I was able to fix some errors, but it's uncovering more errors.Here is my code:
import javax.swing.JOptionPane;
import java.util.*;
import java.text.DecimalFormat;
import java.util.StringTokenizer;
public class Area {
public static void main (String [] args) {
double a, b, c; //Input sides of triangle
double x; //Perimeter of triangle
double area; //Area of triangle
StringTokenizer st;
[code]....
write a program that reads in the year, month, and day of a couple's wedding date and compute thier next wedding anniversary after March 2, 2011.
TThis has to be input in a message dialog box also.
I'm trying to make a method that creates objects of a parameterized type randomly, but also to store the hashCode of different objects created and if at any time the percentage of different objects is less than 50% throw an exception.
This last part is where I've gotten stuck. I have created a population property where I store the different hashCodes and update it in the method adding the new hashCode from the new object. But I don't know how to do for to know if the percentage of different objects is less than 50%.
package fp.tipos.apps;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.List;
import java.util.Random;
public class FactoriaApps {
[Code] .....
I'm currently in the process of creating a shopping cart simulation. The main GUI consists of two lists, one is a list of the inventory. (products stored within a .dat file which is automatically loaded upon launch) The other is blank and is to model my shopping basket. The idea is to be able to scan items from my inventory into the checkout basket. As this is happening i want a text field i created to dynamically update with the cost of all the items in the basket.
Below is the method for my scan button, which is supposed to perform the above :
public void actionPerformed(ActionEvent evt) {
//Get the newly added list values.
JList list = productList.getSelectedValuesList();
double totalAddedValue = 0.0;
double oldCartValue = 0.0;
[code]...
I am trying to do the following java assignment and every thing seems to work fine except when I put a number<4 or >10 it prints both "Invalid grade!"
"You didn't enter any data!" what I wanted is to print only "Invalid grade!" I tried to fix it but I couldn't.
Create a program that asks for results of exams and calculates the mean average of the grades. Grades are floating point numbers between 4 and 10. Program asks for grades until a negative number is typed. If user gives a grade other than a number between 4 and 10, the text "Invalid grade!" will be printed on screen and program asks for another grade. Finally the program prints the number of inputted grades and their mean average on screen as shown in the example print. If no grades were inputted, the notice "You did not input any grades." is the only thing printed on screen.
A double type variable is to be used to store the value of the average.
Program is written to a class called Average.
Example output
Program calculates the average of inputted grades.
Finish with a negative integer.
Input a grade (4-10): 5
Input a grade (4-10): 6,5
Input a grade (4-10): 7,5
Input a grade (4-10): 7
Input a grade (4-10): 0
Invalid grade!
Input a grade (4-10): -4
4 grades inputted.
Average of the grades: 6.5
Java Code:
import java.util.Scanner;
public class apples {
public static void main(String[] args)
int inputNumber=0;
int sum;
int count;
double average;
[Code] .....