JOptionPane, JTextArea, and JScrollPane, Displaying ouput

Question

This is a HW assignment given to the class and I believe I have everything working correctly but I am having trouble displaying all of the information I would need on the output. If you look at TestCashier.java you can see my intended output. I need to know how to make generateReceipt(), average(), makeChange(), and tendered() display on the pane as well. Any help at all will be appreciated. I have been stuck on this portion for quite some time.

If anyone would like to take the extra step in helping me out on my add() and figure out why I can't get it to work when asking the user for each item price. I needed the total to work using add() but I can only get my program to work properly when I manually add them together and assign that value to totalSum. Thank you for taking the time to read this and all input/feedback is appreciated. (Even criticism...I am here to learn)

Cashier.java

package cashier;
import java.text.NumberFormat;

public class Cashier {
    static int numItems;
    static double totalSum,averagePrice,price;
    private int   pennies,nickles, dimes, quarters, dollars;
    private double tendered,change;

    public void Cashier(){
        this.numItems = 0;
        this.totalSum = 0;
    }

    public void average(){
       averagePrice = totalSum/numItems; 
       NumberFormat nf1 = NumberFormat.getCurrencyInstance();
       System.out.println("The average price per item is "+ nf1.format(averagePrice));//Must format

    }
      public void add(String name, Double price) {
        numItems++;
        //totalSum =+price;
    }


    public void tendered(double t) {
       this.tendered = t;
       this.change = tendered - totalSum;
       NumberFormat df1 = NumberFormat.getCurrencyInstance();
       System.out.println("Amount tendered is " + df1.format(tendered));
   }

    void makeChange(Cashier c){

        change = (tendered-totalSum);
        change =change*100;
        NumberFormat df = NumberFormat.getCurrencyInstance();
        System.out.println("The change is: " + df.format(change/100)+"\n");//Must format


        dollars = (int)(change/100);
        change %= 100;


        quarters = (int) (change/25);
        change %=25;


        dimes = (int) (change/10);
        change = change%10;


        nickles = (int) (change/5);
        change = change%5;

        pennies = (int)change;

        System.out.println("The change includes...");
        System.out.println(dollars+" dollars");
        System.out.println(quarters+" quarters");
        System.out.println(dimes+" dimes");
        System.out.println(nickles+" nickles");
        System.out.println(pennies+" pennies");

    }






}

GetData.java

package cashier;


import javax.swing.JOptionPane;
import java.text.NumberFormat;


public class GetData {

    static double getDouble(String c){
        return Double.parseDouble(getWord(c));
    }

    static String getWord(String c){
        return JOptionPane.showInputDialog(c);
    }


}

TestCashier.java

package cashier;
import javax.swing.JOptionPane;
import javax.swing.JTextArea;
import javax.swing.JScrollPane;



import static cashier.Cashier.totalSum;
import java.text.DateFormat;
import java.text.NumberFormat;
import java.util.Date;

public class TestCashier{

    public static void main(String[]arg){
        NumberFormat nf = NumberFormat.getCurrencyInstance();
        Cashier c = new Cashier();

        String name = GetData.getWord(" Enter name of first item");
        double price = GetData.getDouble("Enter price of item");
        c.add(name,price);


        String name2 = GetData.getWord(" Enter name of second item");
        double price2 = GetData.getDouble("Enter price of item");
        c.add(name2,price2);

        String name3 = GetData.getWord(" Enter name of third item");
        Double price3 = GetData.getDouble("Enter price of item");
        c.add(name3,price3);

        String name4 = GetData.getWord(" Enter name of fourth item");
        Double price4 = GetData.getDouble("Enter price of item");
        c.add(name4,price4);

        totalSum = price+price2+price3+price4;



        //make payment 
        double tendered = GetData.getDouble("Enter amount of money for payment");



        generateReceipt(c);
        NumberFormat nf1 = NumberFormat.getCurrencyInstance();
        String s = (name+"\t\t"+nf1.format(price));
        s = s +("\n"+name2+"\t\t"+nf1.format(price2));
        s = s +("\n"+name3+"\t\t"+nf1.format(price3));
        s = s +("\n"+name4+"\t\t"+nf1.format(price4));
        s = s +("\n"+"_______________________________");
        s = s +("\n"+"Total:\t\t"+nf1.format(totalSum));


        s = s +("\n\n"+"The number of items purchased is "+Cashier.numItems+" item(s)");


        c.tendered(tendered);
        c.makeChange(c);

        JTextArea text = new JTextArea(s,30,30);
        JScrollPane pane = new JScrollPane(text);
        JOptionPane.showMessageDialog(null, pane,"THE RIP-OFF STORE",JOptionPane.PLAIN_MESSAGE);



    }
    static void generateReceipt(Cashier c){

       Date current = new Date();
       DateFormat df = DateFormat.getDateInstance(DateFormat.FULL);
       System.out.println("WELCOME TO THE RIP-OFF STORE!");
       System.out.println("Home of the 'not so good' deals...");
       System.out.println("Thank you for stopping by on "+ df.format(current));
       System.out.println("");


    }
}

Answer 1

You need to change your functions to concatenate to a string and return the string. In your function generateReceipt(), edit like so:

static String generateReceipt(Cashier c){
    String s = "";
    Date current = new Date();
    DateFormat df = DateFormat.getDateInstance(DateFormat.FULL);
    s += ("WELCOME TO THE RIP-OFF STORE!\n");
    s += ("Home of the 'not so good' deals...\n");
    s += ("Thank you for stopping by on "+ df.format(current)) + "\n\n";
    return s;
}

and to get the information from that function simply call it like so:

String s = generateReceipt(c);

The same goes for all the functions you need output for from your Cashier.java class. I won't show you each function since it is the same idea for each one. Remember it will be called like so:

s += c.average();

Here is all of your string concatenation from TestCashier and how I have it:

    String s = generateReceipt(c);
    NumberFormat nf1 = NumberFormat.getCurrencyInstance();
    s += (name+"\t\t"+nf1.format(price));
    s = s +("\n"+name2+"\t\t"+nf1.format(price2));
    s = s +("\n"+name3+"\t\t"+nf1.format(price3));
    s = s +("\n"+name4+"\t\t"+nf1.format(price4));
    s = s +("\n"+"_______________________________");
    s = s +("\n"+"Total:\t\t"+nf1.format(totalSum));


    s = s +("\n\n"+"The number of items purchased is "+Cashier.numItems+" item(s)");

    s += c.average();
    s += c.tendered(tendered);
    s += c.makeChange(c);

    JTextArea text = new JTextArea(s,30,30);
    JScrollPane pane = new JScrollPane(text);
    JOptionPane.showMessageDialog(null, pane,"THE RIP-OFF STORE",JOptionPane.PLAIN_MESSAGE);

I haven't looked at your add() function but I'd be happy, too. Chat with me if you need any help.

**Here is a imgur link to what the output looks like on my IDE (IntelliJ Idea): https://i.stack.imgur.com/hXEu9.jpg

EDIT:

You almost had you're add function correct. In Cashier.java, your add() had a statement commented out:

totalSum =+ price; just switch the operators totalSum += price;

Create a getter like getTotalSum() or something along those lines because you always want to use getters and setters instead of accessing class variables directly (at least in most cases). Call it in your TestCashier.java like totalSum = c.getTotalSum(); and it should work correctly. Note how you have name as a parameter for your add() function. Why is that? If you don't need it or use it, scrap it.