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 making a vending machine program to practice inheritance and have a few questions. My superclass is a Soda class, and I'm making subclasses like "Orange soda", "Coke", etc. My first question is, what is the point of the subclass inheriting the instance variables of the superclass? If you have to define them again is there any point in the super class having them? Here is an example of this:
My superclass:
public abstract class Soda {
public double price; public int numAvailable; public String name; public String machineCode;
[code]...
Besides not having to write the vendSoda() method again, what is the benefit of inheritance in a situation like this if you have to define all variables again? My second question is, how could I store all of the code strings from all of the different subclasses in one place? (so when the user enters a code it can search for the code entered to give the desired soda)...
I'm having a major problem in forming the algorithm for my JAVA project, which is a vending machine. I desperately need one in order for it to guide me in making the code. I plan to include an array, switch class to customer and technician portals, item order and retrieval, and change calculator.
So I am making a vending machine and am having trouble knowing what exactly to use or how to go about giving the user a error message depending if they initially added enough money for their choice of drink. So if the user only input 1 dollar, and the drink they select is $1.25, they need to add the $.25, but how do I implement that in this code?
Here is my code along with the zip file just in case.
package vending.sample; import java.util.Scanner; public class VendingSample { public static void main(String[] args) { int coke = 1, sprite = 2, DrPepper = 3, Pepsi = 4, Fanta = 5, Water = 6, selection, i; double change, total;
I have a simple java program to write which tells the user combination of coins that equals to the amount of change i.e:
user input 87
output:
3 quarters 1 dime 0 nickels 2 pennies
How the program remembers the remainder which is passed to the next column of let say dime
i.e
originalAmount = amount; quarters = amount /25; amount = amount % 25; <---- this is confusing for me?!?! how can the integer = integer % 25 dimes = amount / 10; <--- HOW THE PROGRAM remembers the "remainder" instead of the original user input as the code it self tells you dimes = amount where "amount" is what user input NOT remainder.
amount = amount % 10; so on ....;
What I don't understand is HOW this algorithm works. I mean we have int amount where user inputs the number we get the first calculation amount/25 = how many quarters and then amount %25 WILL tell us about the reminder. By looking at this piece of code I would say that the system should start the calculation for the dimes again from the original number since the code says dimes = amount/10 AND amount = amount%10. My understanding is that the calculation should be done from the original user input.
Book or code it self is not clear for me how the reminder is "REMEMBERED" and then pass on to the next calculation>!?!?
UNLESS the code: amount=amount%25 gets the remainder so the next code under it is REQUIRED to read from the last prompt code.
I have developed a code to connecting remote windows M/C from local M/C by using SSH2 (ganymed-ssh2-build209.jar) API. when I run the code its giving below error. Is there any other way to connect remote windows system using java code.
Exception.
java.io.IOException: There was a problem while talking to <host name>:22 at ch.ethz.ssh2.Connection.connect(Connection.java:642) at ch.ethz.ssh2.Connection.connect(Connection.java:460) at Connect.RemoteServer.ConnectWindowsServer.runCommand(ConnectWindowsServer.java:55) at Connect.RemoteServer.ConnectWindowsServer.main(ConnectWindowsServer.java:27) Caused by: java.net.ConnectException: Connection refused: connect
I am making a program which stimulates a bet placer machine for horse race betting for my school project.The program isnt complete yet but till this it doesnt let me input the String a and the program stops after printing "Type "view info" to display info about the different derbies". I use BlueJ 3.1.0 and version of jdk is the latest Java 8 Update 25
import java.util.*; public class Derby { public static void main() { Scanner in=new Scanner(System.in); System.out.println("Welcome to the Horse Racing Bet Placer Machine"); System.out.println("Through this Machine you can place bets on different derbies accross the globe"); System.out.println("Press 1 to choose a Derby"); //Ask user whether he wants to place a bet or not System.out.println("Press 2 if you don't want to place a bet"); int choice=in.nextInt(); //Inputs user's choice if (choice==2) //Determines the user's choice
[code]....
In this screenshot, after printing ''Type "view info" to display info about the different derbies'' it should let me input the value of String a according to the code but instead it stops the program there and doesn't let me input anything
I have a requirement where I have to send a file from a local system to unix box(present on client side) using java code.I have developed a code that is successfully sending the file from local system to client side unix box (I am connecting to client side unix box using VPN) provided I run the code in my eclipse IDE present in local system. But when I am running the same code in the unix box it is throwing null pointer exception.Might be the unix system is not recognising the local system. Please find the code.
I am designing a program that generates 3 random numbers from 1-5 and if 2 match, the user wins $1. If 3 match, the user wins respectively:
All 1s - $5 2s - $10 3s - $25 4s - $50 5s - $100
I first used a loop to run until the user runs out of money or wishes to stop. Then I made 2 methods. 1 to generate the random numbers and 1 to see if the user won any money. I am storing the random numbers in an array called slotnumber.
This is what I have so far but I am getting compiling errors at while (cont == 'y') {
import java.util.Scanner; import java.util.Random; public class SlotMachine {
I had some questions about a theoretical java program. Say you had a java program on a linux server/pc that referenced a folder on that server. And say you had a Client PC (Windows) that had a share folder to that java program.
If that windows client PC tried to run the program would it run (with a GUI if it had one) and would the main directory of the java program still be on the linux server or would it be on the windows computer since that is the computer that is running the program?
Basically I have a program I am trying to find the best way to run it remotely on a windows computer but it references files on the linux server it is located at and needs to put files it creates there as well. I am just trying to make sure I understand my theory here on how the program will run if it IS run remotely.
SlotMachine.java:21: error: illegal start of expression public static void getNums(int [] slots) ^ SlotMachine.java:21: error: illegal start of expression public static void getNums(int [] slots)
[code]....
i keep fixing small things and cannot get it to compile. Below is the original code,
import java.util.Scanner; import java.util.Random; public class SlotMachine { public static void main (String args[]) { int userMoney; Scanner input = new Scanner(System.in); System.out.print("How much money to start with?
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'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.
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 {
