added doc

README.TXT

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+Project: naive-ticket-machine
+Authors: David Barnes and Michael Kolling
+
+This project is part of the material for the book
+
+   Objects First with Java - A Practical Introduction using BlueJ
+   Fourth edition
+   David J. Barnes and Michael Kolling
+   Pearson Education, 2008
+
+It is discussed in chapter 2.
+
+Purpose of project: To illustrate the basics of fields, constructors, and methods.
+How to start this project: Create one or more TicketMachine objects.

README.md

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 # NaiveTicket
 
-the second Objects lab.
+the second Objects lab.
+
+look for the Chapter reading you need in the doc folder.

TicketMachine.java

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+/**
+ * TicketMachine models a naive ticket machine that issues
+ * flat-fare tickets.
+ * The price of a ticket is specified via the constructor.
+ * It is a naive machine in the sense that it trusts its users
+ * to insert enough money before trying to print a ticket.
+ * It also assumes that users enter sensible amounts.
+ *
+ * @author David J. Barnes and Michael Kolling
+ * @version 2008.03.30
+ */
+public class TicketMachine
+{
+    // The price of a ticket from this machine.
+    private int price;
+    // The amount of money entered by a customer so far.
+    private int balance;
+    // The total amount of money collected by this machine.
+    private int total;
+
+    /**
+     * Create a machine that issues tickets of the given price.
+     * Note that the price must be greater than zero, and there
+     * are no checks to ensure this.
+     */
+    public TicketMachine(int ticketCost)
+    {
+        price = ticketCost;
+        balance = 0;
+        total = 0;
+    }
+
+    /**
+     * Return the price of a ticket.
+     */
+    public int getPrice()
+    {
+        return price;
+    }
+
+    /**
+     * Return the amount of money already inserted for the
+     * next ticket.
+     */
+    public int getBalance()
+    {
+        return balance;
+    }
+
+    /**
+     * Receive an amount of money in cents from a customer.
+     */
+    public void insertMoney(int amount)
+    {
+        balance = balance + amount;
+    }
+
+    /**
+     * Print a ticket.
+     * Update the total collected and
+     * reduce the balance to zero.
+     */
+    public void printTicket()
+    {
+        // Simulate the printing of a ticket.
+        System.out.println("##################");
+        System.out.println("# The BlueJ Line");
+        System.out.println("# Ticket");
+        System.out.println("# " + price + " cents.");
+        System.out.println("##################");
+        System.out.println();
+
+        // Update the total collected with the balance.
+        total = total + balance;
+        // Clear the balance.
+        balance = 0;
+    }
+}

bluej.pkg

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+#BlueJ package file
+package.editor.height=275
+package.editor.width=400
+package.editor.x=420
+package.editor.y=175
+package.numDependencies=0
+package.numTargets=1
+package.showExtends=true
+package.showUses=true
+readme.editor.height=487
+readme.editor.width=610
+readme.editor.x=0
+readme.editor.y=22
+target1.editor.height=735
+target1.editor.width=648
+target1.editor.x=50
+target1.editor.y=60
+target1.height=50
+target1.name=TicketMachine
+target1.showInterface=false
+target1.type=ClassTarget
+target1.width=110
+target1.x=80
+target1.y=50

bluej.pkh

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+#BlueJ package file
+package.editor.height=286
+package.editor.width=408
+package.editor.x=419
+package.editor.y=319
+package.numDependencies=0
+package.numTargets=1
+package.showExtends=true
+package.showUses=true
+target1.editor.height=735
+target1.editor.width=648
+target1.editor.x=50
+target1.editor.y=60
+target1.height=50
+target1.name=TicketMachine
+target1.showInterface=false
+target1.type=ClassTarget
+target1.width=110
+target1.x=80
+target1.y=50