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POS: How do I sum the price per item to get the total price?

(Its not finished yet.)
I don't know how to get the total price after asking the user for their order. Example: I ordered 5 Piatos, and I typed end to show the result or total, but it just says 20 but it should be 100 because 20+20+20+20+20 = 100. How do I sum those individual prices so it shows the correct total price without changing the way to order items? (Which is selecting only the letters provided for each item.)
import java.util.Scanner;
public class Point_Of_Sale_System_Real {
static Scanner sc = new Scanner(System.in);
public static void main(String[] args) {
Intro();
}
public static void Intro(){
int Piatos = 20, Vcut = 20;
double itemtotal = 0, itemtotalvisible, itemlone = 0;
String Ia = "a";
String Ib = "b";
System.out.println("Enter the letter that matches the item here: ");
System.out.println("Type \"End\" to stop selecting from the menu." );
String itemselect = "";
do {
itemselect = sc.nextLine();
if (itemselect.equalsIgnoreCase(Ia)){
itemlone = 0 + Piatos;
}
else if (itemselect.equalsIgnoreCase(Ib)){
itemlone = 0 + Vcut;
}
}
while (!itemselect.equalsIgnoreCase("end"));
itemtotalvisible = itemlone + 0;
System.out.println("Total" + itemtotalvisible);
}
}

Each time you make a selection in the do-while loop, you need to update itemtotalvisible. You are merely assigning the last value of itemlone to itemtotalvisible. Hence because the last item you selected was Piatos, itemtotalvisible equals the value of one Piatos item.
The below code is not a complete answer, but hopefully enough to help you fix your code.
double itemtotalvisible = 0;
String itemselect = "";
do {
itemselect = sc.nextLine();
if (itemselect.equalsIgnoreCase(Ia)){
itemlone = 0 + Piatos;
}
else if (itemselect.equalsIgnoreCase(Ib)){
itemlone = 0 + Vcut;
}
itemtotalvisible += itemlone;
}while (!itemselect.equalsIgnoreCase("end"));
System.out.println("Total" + itemtotalvisible);

Arrays with for loop and if statements

So when i i have tried to save and compile everything works fine until I run it. There seems to be an issue with my array syntax. Could someone help me find it?When I do run this program the grades()method outputs "AAA" . What I'm trying to do in this program is read text from a txt file and list each line, outputting a student name and score. Now in the grades() method I am trying to output calculate a letter grade for each of the students grades and make that go into a loop until the last score has been read.
public class ReadData
{
private static String[] names = new String[3];
private static int line;
private static int[] scores = new int[3];
private static float mean;
private static double stdDeviation;
public static void readData() throws FileNotFoundException
{
File file = new File("data.txt");
Scanner scanner = new Scanner(file);
int l = 0;
// float sum = 0 ;
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
String [] words = line.split("\t");
names[l] = words[0];
scores[l] = Integer.parseInt(words[1]);
// sum+=scores[l];
System.out.println(" name: " + names[l] + ", score: " + scores[l]);
l++;
}
// System.out.println(scores[0]+ " " + scores[1]+ " " + scores[2]);
}
public static void fndMean()
{
float mean = ((25+65+89)/3);
System.out.println(" The mean is: " + mean);
}
public static void fndStandard() throws FileNotFoundException
{
double stdDeviation = Math.sqrt(((Math.pow(25-59, 2)+(Math.pow(65-59,2))+
(Math.pow(89-59, 2))))/3);
System.out.println("The Standard Deviation is: " + stdDeviation);
}
Grades method
public static void grades()
{
for(int i = 0; i < (scores.length); i++)
{
if(mean + stdDeviation <= scores[i])
{
System.out.print("A");
}
else if( (scores[i] >= mean+(stdDeviation/3)) &&
(mean +stdDeviation)> scores[i])
{
System.out.print("B");
}
else if( (scores[i] >= mean-(stdDeviation/3)) &&
(mean +(stdDeviation/3))> scores[i])
{
System.out.print("C");
}
else if( (scores[i] >= mean-(stdDeviation)) &&
(mean - (stdDeviation/3))> scores[i])
{
System.out.print("D");
}
else
{
System.out.println("F");
}
}
}

You are re-declaring your variables in methods like fndMean() and fndStandard() when you do the following
double stdDeviation = Math.sqrt(((Math.pow(25-59, 2)+(Math.pow(65-59,2))+
(Math.pow(89-59, 2))))/3);
float mean = ((25+65+89)/3);
You already declare them up top and don't need to do it again, otherwise it will only set the local variables inside the methods and not inside your class. you should do
stdDeviation = Math.sqrt(((Math.pow(25-59, 2)+(Math.pow(65-59,2))+
(Math.pow(89-59, 2))))/3);
mean = ((25+65+89)/3);
Which will set those variables to what you were expecting when you call those methods BEFORE calculating the grades.

This is what fndMean and fndStandard methods print:
The mean is: 59.0
The Standard Deviation is: 26.407069760451147
Sum of mean and stdDeviation is 85.40706976045115.
Now, the condition if(mean + stdDeviation <= scores[i]) checks whether that sum is less than equal to score[i] and if yes, prints 'A'. It can be true in either of these two cases:
Values in second column (tab) in txt files are all more than 85
score array gets altered between two method calls
Printing score value before those conditions should give you some more idea.

How to aggregate values stored inside an array in java

I am creating a simple games score report generator program which takes input and turns it into a .txt file. It takes a name, a game name, an achievement score and minutes played and I want to be able to tally up the amount of games input, add up the achievement score and also add up the minutes (and convert to hours).
This is an example of how my output to .txt looks at the moment -
This is an example of how I would like an output to look -
How do I aggregate data that was input into the console and stored in an array to get results that I want?
PrintWriter writer = new PrintWriter(new FileOutputStream("Gaming Report Data", true));
writer.println("Player : " + gamerName);
writer.println();
writer.println("--------------------------------");
writer.println();
String[] report = gamerReport.split(":");
writer.println("Game: " + report[0] + ", score= " +report[1] + ", minutes played= " +report[2]);
writer.println();
writer.close();
Source code
package JavaProject;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;
import java.nio.file.*;
public class JavaProject {
private static final int minutesPlayed = 0;
private static char[] input;
public static void main(String[] args) {
//variables
int hrs = minutesPlayed * 60;
int mins;
String gamerName, gamerReport = null;
int gameCount;
int errorCount;
//Main data storage arrays
String[] gameNames = new String[100];
int[] highScores = new int[100];
int[] minutesPlayed = new int [100];
#SuppressWarnings("resource")
Scanner Scan = new Scanner(System.in);
//formatting for output and input
System.out.println("////// Game Score Report Generator \\\\\\\\\\\\");
System.out.println(" ");
//User enters either their name or quit. Entering a name will move on to next part
for ( ; ; )
{
System.out.print("Enter your Name.");
System.out.println(" ");
gamerName = Scan.nextLine();
for(int b = 1; b < 99; b++ ) { //this is making the code loop 100 times
//user is given an example of input format
System.out.println(" ");
System.out.println("Input Gamer Information " + "Using Format --> Game : Achievement Score : Minutes Played");
System.out.println("FALSE DATA FORMAT WILL CAUSE ERROR");
System.out.println(" ");
//another data input guide which is just above where data input is in console
System.out.println("Game : Achievement Score : Minutes Played");
gamerReport = Scan.nextLine();
String[] splitUpReport; // an array of string
if (gamerReport.equalsIgnoreCase("quit")) {
System.out.println("You have quit!");
return;
}
splitUpReport = gamerReport.split(":");
int i = 0;
//copy data from split text into main data storage arrays
gameNames[i] = splitUpReport[0];
highScores[i] = Integer.parseInt(splitUpReport[1].trim() );
minutesPlayed[i] = Integer.parseInt(splitUpReport[2].trim());
//output to file using a PrintWriter using a FileOutPutStream with append set to true within the printwriter constructor
//
try
{
PrintWriter writer = new PrintWriter(new FileOutputStream("Gaming Report Data", true));
writer.println("Player : " + gamerName);
writer.println();
writer.println("--------------------------------");
writer.println();
String[] report = gamerReport.split(":");
writer.println("Game: " + report[0] + ", score= " +report[1] + ", minutes played= " +report[2]);
//writer.println("Games Played : " + minutesPlayed);
writer.close();
} catch (IOException e)
{
System.err.println("You have made an error with data input");
}
}
System.out.println("You have quit!");
}
}
public static char[] getInput() {
return input;
}
public static void setInput(char[] input) {
JavaProject.input = input;
}
}

So I am assuming that your array data structure looks like this:
Object[] report = new Object[] {new String(), new Integer(), new Integer()}
where the first entry is the game name, the second is the score, and the third is the time played.
I would suggest that you bundle this data into its own object instead of tracking every 3 positions in an array. Try:
public class Game
{
private String name; public String getName() { return name; }
private int score; public int getScore() { return score; }
private int minutesPlayed; public int getMinutesPlayed() { return minutesPlayed; }
public Game(String name, int score, int minutesPlayed)
{
this.name = name;
this.score = score;
this.minutesPlayed = minutesPlayed
}
#Override
public String toString()
{
return "Game: " + name + ", score= " + score + ", minutes played= " + minutesPlayed);
}
}
You can then use this object to represent game data and hold and array of these objects like this:
Game[] games = new Game[]{
new Game("Game 1", 52, 89),
new Game("Game 2", 57, 58),
new Game("Game 3", 67, 86)
};
This array allows us to access each game as a single entity; for example games[0] would get the reference to the 1st game object in the array. These games can have their data accessed by calling the "getters" for the 3 fields contained in the Game object. games[0].getName() would return the name for the first Game object; likewise, games[0].getMinutesPlayed() would return the minutes played for the first game.
Since we overrode the toString method offered to all classes from java's object class to output a string of the data desired in the way your first file I/O was structured. You can call writer.println(games[i]) where i is and index in your array of games to write the data for a individual game.
To concatenate this data into the output you desired. We can do the following:
// get the number of games played
int gamesPlayed = games.length;
// get the raw data on score and time
int totalScore = 0;
int totalMinutesPlayed = 0;
for(int i = 0; i < games.length; i++)
{
totalScore += games[i].getScore();
totalMinutesPlayed += games[i].getMinutesPlayed;
}
// compile the output string
String output = "Games Played: " + gamesPlayed
+ "\n\nTotal Achievement: " + totalScore
+ "\n\nTotal Time: " + totalMinutesPlayed
+ " (" + totalMinutesPlayed / 60
+ " hours and " + totalMinutesPlayed % 60
+ " minutes).";
// write the string to the file
writer.println(output);

Suggestion:
Create a model of the data as a new simple class:
public class GameReportModel{
String gamename = null;
String username = null;
int score = 0;
int minutesplayed = 0;
}
Now you can use an ArrayList of this model to store data before generate the report:
//Declare
ArrayList<GameReportModel> myArray = new ArrayList<GameReportModel>();
//Populate (example) for each input
GameReportModel myobj = new GameReportModel();
myobj.gamename = "My Game"; //<<from input source
myobj.username = "John"; //<<from input source
myobj.score = 20; //<<from input source
myobj.minutesplayed = 45; //<<from input source
myArray.add(myobj);
// Iterate
for(GameReportModel line : myArray){
writer.println("Player : " + line.username);
... and sumarize for each Player
}
Now you can build some scripts to sort by name, game. This method turn it easy but consume more virtual machine resources (memory and steps). But you can manipulate data with another perspective.
Add and remove Array elements easy.

Java - Array outputing null

My program is supposed to output labels. All of the input works when I run it but the output is wrong and all that it outputs is null, for every part of the label except for the box number.
import javax.swing.JOptionPane;
public class MailOrderpractice {
static String nameAddressArray[] = new String[7];
public static void main(String[] args) {
// declare variables
String nameAddressArray[] = new String[7];
String numBoxesInput;
int numBoxes;
String enterAnother = "Y";
int counter;
getLabelData();
numBoxesInput = JOptionPane.showInputDialog("Enter number of boxes in the order:");
numBoxes = Integer.parseInt(numBoxesInput);
// begin outer loop logic that determines when user is finished entering mail orders
while (enterAnother.equalsIgnoreCase("Y")) {
counter = 1;
// begin the inner loop to display a label and increment the counter
while (counter <= numBoxes) {
System.out.println(nameAddressArray[0] + " " + nameAddressArray[1] + " " + nameAddressArray[2]);
System.out.println(nameAddressArray[3]);
System.out.println(nameAddressArray[4] + ", " + nameAddressArray[5] + " " + nameAddressArray[6]);
System.out.println("Box " + counter + " of " + numBoxes);
System.out.println();
counter = counter + 1;
}
enterAnother = " "; // initialize the variable to something other than "Y" before sending the prompt
enterAnother = JOptionPane.showInputDialog("Do you want to produce more labels? Y or N");
while (!enterAnother.equalsIgnoreCase("Y") && !enterAnother.equalsIgnoreCase("N")) {
enterAnother = JOptionPane.showInputDialog(null, "Invalid Response. Please enter Y or N.",
"DATA ENTRY ERROR", JOptionPane.ERROR_MESSAGE);
} // end while
if (enterAnother.equalsIgnoreCase("Y")) {
getLabelData();
numBoxesInput = JOptionPane.showInputDialog("Enter number of boxes in the order:");
numBoxes = Integer.parseInt(numBoxesInput);
} // end if
} // end while
System.exit(0);
}
public static void getLabelData() {
nameAddressArray[0] = JOptionPane.showInputDialog("Enter title (Mr., Ms., Dr., etc.): ");
nameAddressArray[1] = JOptionPane.showInputDialog("Enter first name: ");
nameAddressArray[2] = JOptionPane.showInputDialog("Enter lastname: ");
nameAddressArray[3] = JOptionPane.showInputDialog("Enter street address: ");
nameAddressArray[4] = JOptionPane.showInputDialog("Enter city: ");
nameAddressArray[5] = JOptionPane.showInputDialog("Enter state (IL, MO, etc.): ");
nameAddressArray[6] = JOptionPane.showInputDialog("Enter zip (e.g., 62025): ");
}

The array nameAddressArray is declared twice. You have a static field
static String nameAddressArray[] = new String[7];
You also have a local variable with the same name in the main method.
String nameAddressArray[] = new String[7];
Your main method is putting values into the second array, whereas your getLabelData method is using the values from the static field, and these are all the initial value (null).
One way to solve this problem is to just get rid of the local variable. Then both parts of the code will use the same array.
Alternatively, you could get rid of the static field, and pass the array as a parameter to the getLabelData method. This is probably a better solution, as mutable static fields are generally not a good idea.

you just need to comment this line into Main method(),
// String nameAddressArray[] = new String[7];

How to use ArrayLists to output (.txt file) a report in a specific format that lists scores of athletes?

I'm having a bit of trouble with this project, and would greatly appreciate some help.
Here's a link to it:
http://www.cse.ohio-state.edu/cse1223/currentsem/projects/CSE1223Project11.html
The basic gist is it's "A program that reads in a text file that uses a specific input format and uses it to produce a formatted report for output."
Specifically:
"For this lab you will write a Java program that produces a simple formatted report. The program will prompt the user to enter a file name. This file must contain information in a specific format (detailed below). Each "block" of the file contains information for one player in a competition -- the name of the player followed by a number of different scores that that player achieved. The program should find each player's average score, median score and best and worst scores and display them in a line on the final summary report. The program should also determine which player has the highest average score and which player has the lowest average score."
I get the following errors when I try and compile it:
Enter an input file name: Project11.txt
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException... -1
at java.util.ArrayList.elementData(Unknown Source)
at java.util.ArrayList.get(Unknown Source)
at Project11.getMedian(Project11.java:68)
at Project11.main(Project11.java:27)
Sorry for not clarifying.
Line 68 is: return (inList.get(Middle - 1) + inList.get(Middle)) / 2;
Line 27 is: int median = getMedian(List);
Hope that helps.
Here's my code:
import java.io.;
import java.util.;
public class Project11 {
public static void main(String[] args) throws IOException{
Scanner in = new Scanner(System.in);
System.out.print("Enter an input file name: ");
String input = in.nextLine();
File inputFile = new File(input);
List<Integer> List = readNextSeries(inputFile);
int median = getMedian(List);
int mean = getAverage(List);
int max = getMaximum(List);
int min = getMinimum(List);
System.out.print("Enter an output file name: ");
String out = in.nextLine();
PrintWriter outputFile = new PrintWriter(out);
System.out.println("Median = " + median);
System.out.println("Mean = " + mean);
System.out.println("Max = " + max);
System.out.println("Min = " + min);
outputFile.println(median);
outputFile.println(mean);
outputFile.println(max);
outputFile.println(min);
outputFile.close();
}
// Given a Scanner as input read in a list of integers one at a time until a negative
// value is read from the Scanner. Store these integers in an ArrayList<Integer> and
// return the ArrayList<Integer> to the calling program.
private static List<Integer> readNextSeries(File f) {
ArrayList<Integer> List = new ArrayList<Integer>();
try {
Scanner fileScan = new Scanner(f);
while (fileScan.hasNextInt()) {
int value = Integer.parseInt(fileScan.next());
List.add(value);
}
} catch (FileNotFoundException e) {}
return List;
}
// Given a List<Integer> of integers, compute the median of the list and return it to
// the calling program.
private static int getMedian(List<Integer> inList) {
int Middle = inList.size() / 2;
if (inList.size() % 2 == 1) {
return inList.get(Middle);
}
else {
return (inList.get(Middle - 1) + inList.get(Middle)) / 2;
}
}
// Given a List<Integer> of integers, compute the average of the list and return it to
// the calling program.
private static int getAverage(List<Integer> inList) {
int total = 0;
int average = 0;
for(int element:inList){
total += element;
}
average = total / inList.size();
return average;
}
private static int getMaximum(List<Integer> inList) {
int largest = inList.get(0);
for (int i = 1; i < inList.size(); i++) {
if (inList.get(i) > largest) {
largest = inList.get(i);
}
}
return largest;
}
private static int getMinimum(List<Integer> inList) {
int smallest = inList.get(0);
for (int i = 1; i < inList.size(); i++) {
if (inList.get(i) < smallest) {
smallest = inList.get(i);
}
}
return smallest;
}
}
Thank you very much for any input.

Your getMedian(...) method doesn't handle the empty list case. Say you have an empty list (list of size 0), what do you think will happen? It will hit this line:
return (inList.get(Middle - 1) + inList.get(Middle)) / 2;
This inList.get(Middle - 1) is the same as inList.get(0 - 1) if the size of the list is 0. You want to make sure you methods handle all different cases. I'd recommend adding an if statement for this specific case (throw an Exception or give output so user knows what is wrong).
NOTE: This "all cases handling" applies to all your methods.