NaiveTicket/TicketMachine.java

/**
 * 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;
    // Exercise 2.15
    private int status;

    /**
     * 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()
    {
        //2.39 set price to 1000 and remove input parameter
        //2.42 constructor with parameter to specify price
        //2.58 Better ticket machine
        price = 0;
        balance = 0;
        total = 0;
    }

    //public TicketMachine()
    //{
        //2.42 constructor with default value of price
        //price = 500;
    //}

    /*
     * Exercise 2.30/2.41: Assign a value to the price field
     */
    public void setPrice(int ticketCost)
    {
        price = ticketCost;
    }

    /*
     * Exercise 2.31: Add a value to the score field
     */
    public void increase(int points)
    {
        int score = points;
    }

    /*
     * Exercise 2.32: Subtract a value from the price field
     */
    public void discount(int amount)
    {
        price = price - amount;
    }

    /**
     * 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)
    {
        if(amount >= 0){
            balance = balance + amount;
        }
    }

    /**
     * Return the total amount of money collected by this machine.
     */
    //Exercise 2.24
    public int getTotal()
    {
        return total;
    }

    /**
     * Print message when incorrect amount of money is inserted
     */
    //Exercise 2.33
    public void prompt()
    {
        System.out.println("Please insert the correct amount of money.");
    }

    /**
     * Print message showing price of a ticket
     */
    //Exercise 2.34
    public void showPrice()
    {
        System.out.println("The price of a ticket is " + price + " cents.");
    }

    /**
     * Print message showing price of a ticket
     */
    //Exercise 2.40
    public void empty()
    {
        total = 0;
    }

    /**
     * Print message showing price of a ticket
     */
    //Exercise 2.55
    public int emptyMachine()
    {
        return total;
        //total=0;
    }

    /**
     * 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;
         */

        /*
        if(balance >= price) {
        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 price.
        total = total + price;
        // Reduce the balance by the price.
        balance = balance - price;
        }
        else {
        System.out.println("You must insert at least: " +
        (price - balance) + " more cents.");
        }
         */

        int amountLeftToPay = price - balance;

        if(amountLeftToPay <=0){
            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 price.
            total = total + price;
            // Reduce the balance by the price.
            balance = balance - price;
        } else {
            System.out.println("You must insert at least: " +
                (price - balance) + " more cents.");
        }
    }

}

/* EXERCISES
 * 2.1: call void printTicket()
 * 2.2: price that was entered
 * 2.3: The ticket prints regardless
 * 2.4: [practice ticket machine]
 * 2.5: Yes, price is different.
 * 2.6: public class Student; public class LabClass
 * 2.7: Order of statement matters
 * 2.8: It is possible to leave this out, the class will be assigned default access modifier
 * 2.9: fields: price, balance, total; 
 * constructors: public TicketMachine(int ticketCost); 
 * methods: getPrice, getBalance, insertMoney, printTicket
 * 2.10: no return type defined
 * 2.11: int, Student, Server
 * 2.12: alive, tutor, game
 * 2.13: Order of statement matters
 * 2.14: field declaration requires a semicolon
 * 2.15: Shown in code
 * 2.16: Student 
 * 2.17: title of type String, and price of type double
 * 2.18: fields: title, price, author, publisher, publish date
 *  types: string, double, string, string, date 
 * 2.19: name = petsName;
 * 2.20: The problem when adding int is the ticketCost was not recognized as price
 *  Assignments should not re-declare the field type. This needs to be done in fields section.
 * 2.21: getPrice returns a passed value and getBalance returns a set value.
 * 2.22: getBalance - "How much money do I owe or am I owed?"
 * 2.23: No, the variable does not need to have the same name as the method
 * 2.24: new getTotal method created above.
 * 2.25: error "missing return statement"
 * 2.26: getPrice returns an integer, printTicket does not return anything (void)
 * 2.27: They are actions and don't return anything.
 * 2.28: (Practicing methods)
 * 2.29: There is a return type included
 * 2.30-2.34: Shown in Code
 * 2.35: Different outputs because the price is variable
 * 2.36: "price" string would display instead of a variable
 * 2.37: Same output as 2.36
 * 2.38: No, they cannot show variable prices because they are outputing a string
 * 2.39: Objects cannot pass a parameter to the ticketmachine
 * 2.40: Mutator method
 * 2.41: Setter method
 * 2.42: Shown in code
 * 2.43: (Practicing methods)
 * 2.44: negative values do not affect balance
 * 2.45: Booleans are well suited to be controlled by a type with only two different values
 * 2.46: Shown in code
 * 2.47: No because there is a check to make sure price is not greater than balance
 * 2.48: +, -, /, *, %
 * 2.49: saving = price * discount;
 * 2.50: mean = total / count;
 * 2.51: if(price > budget){System.out.print("Too expensive")}else {System.out.print("Just right")}
 * 2.52: if(price > budget){System.out.print("Too expensive, your budget is only " + budget)}else {System.out.print("Just right")}
 * 2.53: it is setting balance as 0 before returning it.
 * 2.54: return statement ends the execution of a method
 * 2.55: Shown in code
 * 2.56: It is an accessor because method ends after return statement
 * 2.57: Shown in code
 * 2.58: setPrice method can be called to set price based on user selection
 */