I was tasked with creating a program that encrypts a line of text (for example, CANDY) by shifting the letters X amount of times. For example, if the user inputs the sentence CANDY and selects a shift of 5, the output would be: HFSID. I got this part working fine. The issue I am having is with the decryption part of the program.
This is simply the reverse of the above, as the user would enter the phrase HFSID, with a shift of 5, and the program would output: CANDY. It works fine, all except for one letter, being the "F" letter. With my code, when I enter the above word to be decrypted it outputs: C[NDY
Obviously, that [ bracket is not an 'A'. I realise the issue falls with the equation, Here is my code:
public class SimpleEncryption {
/**
* @param args the command line arguments
*/
static int answer;
public static void main(String[] args) {
String cipher = JOptionPane.showInputDialog(null, "Please enter a sentence or word that you wish to encode or decode. This program uses"
+ " a basic cipher shift.");
I'm trying to make a simple Caesar cipher that takes in a String as the first argument and a integer shift as the second argument. Namely, there appears to be a problem with the loop and how I have declared the array - I want the converted characters to be put into a new array called newCharacterArray, converted back to a String and displayed in the command prompt window.
public class Caesar { public static void main(String inString, int k) { System.out.println("String: " + inString); char inStringArray[] = inString.toCharArray();
I am creating a simple ArrayList program that would enable one to input their username to it using a scanner. However, i am getting this error: "Exception in thread "main" java.lang.NullPointerException
at home.Members.addUser(Members.java:16) at home.Main.main(Main.java:14)"
Here is the code! :
Main.java class Java Code: import java.util.Scanner; public class Main {
I'm trying to fix this logic error in my slot machine game where no matter what slot combo comes up, it says you have won $10 and proceeds to add that amount to the balance and subtract the bet amount to the balance, even though it is not a winning combo! I've been trying to solve that and when doing so, I commented out Slot1.randNum1 == 0, Slot2.randNum2 ==0, and Slot3.randNum3 ==0 and anything relating to see if that was the problem, and it seemed like it was, because after that, the logic error described above was gone, but in doing so, the loss/win counter didn't increment, nor did the program pick up on the winning combos. However, I do not know why commenting out anything relating to randNum ==0 would cause that.
Here is the code for the processing (as you can see, some parts are commented in attempt to fix the logic error, but right now the code below is for the logic error that keeps on telling that the user has won):
public void askData () { title (); int betAmount; while (true) { try { c.setCursor (3, 1);
My code runs and populates an arraylist. However my break statement, while stopping the loop ends up being added to the arraylist. And I'm not sure how to fix this error.
public static void main(String args[]) throws Exception { // declaring variables String input = ""; // creating array list ArrayList<String> nameList = new ArrayList<String>();
I've decided to go back to basics and start using pseudocode--but i want to see if my logic is correct.so here's the first program:each delegate to a certain conference must wear a tag showing their name and the organization they represent as shown below:
######################
#### Annual Conference #####
######################
##NAME: ##
######################
##ORGANIZATION: ##
######################
write a class called TagMaker that prints out tags. supply methods to (a) set the name (b) set the organization (c) print tag with the name and organization (d) clear the name and organization (e) print a blank tag. then write a TagTester class to test the TagMaker class. so this is the pseudo code (or logic) that i've come up with for the program:
TagMaker main class:
-Prompt user to enter in first and last name, as well as their organization.
-Read user input for the name and organization.
-Return user input.
-Write conference tag showing the person's information.
-Clear information.
-Print blank tag.
1. i assume i would have to import a few java libraries.
Java Code: java.util.Scanner mh_sh_highlight_all('java'); and Java Code: java.io.*; mh_sh_highlight_all('java');
2. afterwards i would declare the instance variables (private, i assume). static too? so for example: Java Code: private static string firstName mh_sh_highlight_all('java');
3. i'm not sure if this program requires a constructor...being that i'm supposed to clear the program at the end anyway.
4. i create a public class declaring my input variable. example: Java Code: String first = firstName.nextLine(); mh_sh_highlight_all('java');
5. so i then i have to create methods that get/set the user input.
getter/setter example:
Java Code:
public String getFirst(){ return first; } public void setFirst(){ this.first = new first; } mh_sh_highlight_all('java');
6. to print out both tags, would i write most of the code as part of a loop and make an "if" statement where the user input is valid, it prints out a tag with information, and another "if" statement that would automatically clear the buffer?
7. last i would create a tester class that would primarily be responsible for the program's output.
import javax.swing.JOptionPane; public class Calculator { public static void main ( String args[] ) { double n1 = Double.parseDouble(JOptionPane.showInputDialog(" Enter first number: ")); double n2 = Double.parseDouble(JOptionPane.showInputDialog(" Enter second number: ")); String x = JOptionPane.showInputDialog("Enter operator: "); double result;
[code].....
Write a program that mimics a calculator. The program will need to accept as input two numeric double values, and accept the operation to be performed as the third input. The operation to be performed will be input in the form of the character representing the java operator for the operation to be performed (i.e + for addition, - for subtraction, * for multiplication, / for division, or % for modulus). Once the program has read these 3 inputs it should output the numbers, the operator, and the result. (For division, if the denominator is zero, the program will output an appropriate message (i.e division by zero is an invalid operation). Please use the JOptionPane class for both accepting the required inputs and for the required output demonstrated below.Some sample output may look as follows:
So I have this 2D array that contains some Object foo.
[f] [f] [f][f]
[3][3][3][3]
[b][b][b][b]
[x][x][x][x]
[ ][ ][ ][ ]
[ ][ ][ ][ ]
[ ][ ][ ][ ]
I want to shift all the rows down one unit, starting for the rows containing x. So the x row is first shifted to row 4. then the b row shifted to where the x row was, row 3 and so on. My question is:
1. How can I check if the next row is empty
2. How do I shift a row down
Here's my attempt:
Java Code:
//board is the 2D array defined elsewhere public void shiftRowDown(){ int counter = 0; int rowCounter = 0; for (int i = 0; i < this.board.length; i++) {
Any way to shift in a range from 0-9 when I already have the shift value.
The reason I am asking this is because I am writing a telephone validation program and I got most of it complete and all I need to do now is the shift an encrypted phone number given to me by the user, and shift it however many times my shift value is.
Example: I am trying to get this phone number, 545-319-8712 to become 212-086-5489. The shift value is 3. So basically since the phone number given to me is 3 numbers higher than the phone number I am trying to get, so if the first number I receive from the user is higher than 2 then I would shift the number the user gave me down by the shift value I have already gotten.
5 shift down 3 = 2, 4 shift down 3 = 1, etc. But I also want to know how I can make a number like "1" to shift down 3 to become 8. This is the range; 0, 1, 2, 3, 4, 5, 6, 7, 8, 9.
If I have to shift a number down 4 spots and I get the number 1 from the user than I want to get the number 1 to first down four times to become 7.
[1] -> 0 -> 9 -> 8 ->[7]
Basically if I have to shift a number down 4 and the number is less than or equal to 3 then I want it to continue from 9 .
Then just reverse the steps if I have to shift a number up, USER gives me "090", i want "212" I shift the number up by 2.
This piece of java software I am responsible for is running throughout numerous locations in my country, there is only 1 location which has trouble with the dates being displayed incorrectly, birthdates of clients are displayed as a day earlier. It seems pretty safe to say it is a problem on their end... But still, they're asking me for an explanation as to why java would treat a date differently in this rare case.
The date (a birthdate) comes from an oracle database, it is a date without a time (trunced date). It enters the application as a member of the client-class, it is NOT being set or changed after that. It goes through several layers in the application, then ends up in a GUI class which unwraps it from the "client"-object and puts a SimpleDateFormat (new SimpleDateFormat("dd-MM-yyyy")) on it. My first and only hunch was the timezone settings, but that seems to be OK!
I'm trying to write a program that asks a user how many high scores they want on a table, then the users types the inital highscores and is repeatedly asked to place more high scores on the table, which if larger than any existing high score, will take its place and shift the other scores down.
Although for the shifting and inserting of that next score the code just doesnt seem to be working, the insertScore function is where im getting the main exception, and im not sure why?
import java.util.Arrays; import java.util.Collections; import java.util.Scanner; public class HighScores { public static void main(String[] args) {
I'm getting back into the swing of things with Java after using I'm asked to utilize a simple GUI in order to take in the starting data, I cannot seem to get this to work. I'm getting this error Exception in thread "main" java.lang.NullPointerException
at java.awt.Container.addImpl(Unknown Source) at java.awt.Container.add(Unknown Source) at Input.buildPanel(Input.java:53) at Input.<init>(Input.java:27) at InputDemo.main(InputDemo.java:5)
I have my program set up I thought correctly. When I click the buttons, nothing is happening.
import javax.swing.*; import java.awt.*; import java.awt.event.*; public class RobertMaloneChapter18 extends JFrame { //set final sizes for window private static final int WIDTH = 300; private static final int HEIGHT = 200;
I was learning Java and there was this exersize to construct a simple pyramid of prespecified height and width. The program i wrote is turining up with the wrong result.
package asgn2; import acm.graphics.*; import acm.program.*; public class pyramid extends GraphicsProgram { private static final int BRICK_WIDTH = 30; private static final int BRICK_HEIGHT = 12; private static final int BASE_BRICKS =14;
This is a simple project that i was using to test my current java knowledge (kinda like revision) and for that i used two classes to make a simple averaging program. i know i0m making it more difficult but like i said i'm testing myself but i come up with an unexpected error. Here's the code:
- 1st Class
import java.util.Scanner; public class Main { public static int num; public static int total = 0; public static int average;
[Code].....
Now the problem is after inputing the numbers it doesn't give me the average but the value of 0.
I'm trying to read lines from a textfile and count all the words using String Tokenizer. However I keep getting an error "Unhandled exception type FileNotFoundException" on my IDE(Eclipse) referring to lines 13 and 8. When I let the IDE automatically, and I've even tried typing this manually, insert a try-catch block more errors show up concerning inputFile. When I insert the throws FileNotFoundException for each method it compiles but after running it gives me a FileNotFoundException for textfile.txt. What's even more interesting is that when I copy the .java file out of the IDE project folder, place it in a random empty folder on the Desktop with the textfile.txt, and try running it through command line, it gives a NoSuchElementException: No line found.
I have to write an encryption/decryption program for a sentence entered by the user that uses arrays. Here is my code so far. I'm kind of lost on what to do next in the code.
import java.util.Scanner;
/*Program that encrypts then decrypts a sentence Encryption */ public class Encryption extends java.swing.JFrame{
My code below is trying to make a connect four program without GUI. I'm having trouble with getting the players to make their moves. What should I put in my "makeAMove" method...
Java Code:
public class Connect
final static int MAXROW = 6; final static int MAXCOL = 7; public static void main(String[] args){
I am having a difficult time writing what started out as a simple vending machine program. As I go on though, it seems that I'm overcomplicating it and it is getting messy, so I have resorted to the forum before I really get off the path. how to clean it up? I'm going to list a few of the problems I am having with the code below:
1. The user is supposed to enter his/her money and the program is to read each value separately (Do-While loop) and keep a running total of the money entered. I can't seem to get the right code format to do this. I was trying to do this with the variable total and so that is why the total exists in the switch statement, but it did not work.
2. In the second Do-While statement, is there a way to kick back an error when their are insufficient funds to purchase an item? Instead of getting a negative change return.
package practice; import java.util.Scanner; public class Practice { public static void main(String[] args) { double count, total; int item; //Display Available Options To Customer Scanner input = new Scanner(System.in); System.out.println("*VENDING MACHINE*");
I'm very new to Java (I literally started learning it yesterday) and I've been working on a simple program that's meant to simulate interactions between optics objects and light rays.
Everything has been going really well, except that my mirrors only reflect the first ray that comes in contact with them.
Here's a screenshot : 2014-09-13 at 7.39.23 PM.jpg
I wrote 7 classes:
Main class to create the optics objectOptics class. the most important class that uses a recursive function to detect the nearest intersection point of a ray with the nearest optics object. It then calculates a reflected ray and inputs it back into the function until no intersections are found or the max recursion depth is met.Ray. creates a rays (in parametric form O + tD where O is the origin, D is the direction and t is a non-negative scalar)Object. empty abstract class used for polymorphism (so when i add more optics objects like prisms and lenses they'll share the object type)Mirror. Basically a line segment created with the Line classLine. Creates a line segmentDraw. JComponent with paintComponent function that loops through an array of shapes and draws them to the screen.
What I know so far is that the problem boils down to the checkRay() function in the Optics class. When a mirror has already reflected a ray, the line:
Intersection sec = new Intersection(ray,(Mirror)obj);
creates an intersection with a null point.
I debugged it line by line and found the problem was that my variable 't' (that is the parameter for the parametric line which represents the mirror) in the Intersection class got big values when it's meant to be between 0 and 1 (since it's a line segment), which resulted in the function returning null (as it should when 't' is not between 0 and 1).
I've confirmed with tests that this has nothing to do with the specific mirror or angle of incidence. It only occurs when a mirror has already been intersected with by a ray.
I've found out that my function:
public PVector getNormal(PVector D){ D.normalize(); return new PVector(D.y,-D.x); }
Changes the value of the 'D' PVector of the mirror inside my 'objects' ArrayList. How can it access the private PVector 'D' from outside the Mirror class? This normalization to the direction vector is what causes the Intersection class to return null the second time around!
The problem was that in the getNormal function, the input vector argument was a reference to the 'D' vector for the mirror in my 'objects' ArrayList so the .normalize() function acted upon the original vector, changing it's value and screwing things up. The two classes I talked about:
Optics: (note line 64. this line returns a null intersection when it shouldn't)
package ofer.davidson; import java.util.ArrayList; public class Optics { //Arrays to store all the optics objects and rays that are created ArrayList<Object> objects; ArrayList<Ray> rays;
So I'm trying to make a simple program which takes in an argument (target) and then looks through an ArrayList of strings. If it finds a string that begins with (target) then it will return the index of that string. If it doesn't find a string which begins with (target) then it will return -1 instead.
For some reason, the program is always returning -1, rather than the index of the string within the ArrayList when there is one which matches the search criteria.
Here is the code:
public int getIndex(ArrayList<String> text, String target) { int i = 0; int index = -1; boolean found = false;
Write a program to simulate the operation of a simple robot. The robot moves in four directions: Forward, backwawrd, left, and right. The job of the robot is to move items and place it in the right slots in each station. There are 8 stations plus the pickup station. Pick up station is the initial start where the robot picks the items. 8 items can be placed on each station. The nearest station must be filled before placing items on the next station. The items are marked with identification or serial numbers. The items with odd serial number go to the right and items with even number go to the eft. The last slot, number 7 is reserved for light items which are less than 80kg. The serial number is a five digit number, the MSB digit 5 indicates that the product must be placed in the fifth station which is keeping the product at 20 degree F.
I need getting started designing and creating a program that calculates simple and compound interest. Simple interest in this case means that interest is only applied to the original amount. For instance, if a person deposits $1000 at 10% annual interest, then after one year they would have $1100 (the original $1000 plus the $100 interest) and after two years they would have $1200 (the original $1000, plus the $100 earned the first year, plus the $100 earned the second year).
With compound interest, the interest is applied to all money earned. So, starting with $1000 at 10% annual interest, after one year the user would have $1100 (the original amount plus $100 interest) and after two years the user would have $1210 (the $1100 they started with at the beginning of the year plus the $110 interest).
The requirements of this program are:
-Create a class that will hold methods to calculate the interest. Do not include the main method in this class. -In the class that is used to calculate the interest, include a method to print to the screen, by interest period, the starting amount for the period, the interest earned for the period, and the total amount at the end of the period. Note that each period represents the time frame for how often it is updated. If annual is selected the period is every year. If it is semi-annual it is every six months. If it is quarterly it is every three months. -Create a demo class that will use your interest calculation class. Prompt the user for the original amount, the type of interest (simple or compound), the annual interest rate, and whether it is updated annually, semi-annually, or quarterly. Use method calls to your calculate interest class to do all calculations and display the result. Loop the program until the user chooses to quit.
