Chapter 2 of the BlueJ book. Walk through many of the chapters exercises.

TicketMachine.java 2.6KB

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  1. /**
  2. * TicketMachine models a naive ticket machine that issues
  3. * flat-fare tickets.
  4. * The price of a ticket is specified via the constructor.
  5. * It is a naive machine in the sense that it trusts its users
  6. * to insert enough money before trying to print a ticket.
  7. * It also assumes that users enter sensible amounts.
  8. *
  9. * @author David J. Barnes and Michael Kolling
  10. * @version 2008.03.30
  11. */
  12. public class TicketMachine
  13. {
  14. // The price of a ticket from this machine.
  15. private int price;
  16. // The amount of money entered by a customer so far.
  17. private int balance;
  18. // The total amount of money collected by this machine.
  19. private int total;
  20. public void prompt()
  21. {
  22. System.out.println("Please insert the correct amount of money.");
  23. }
  24. /**
  25. * Create a machine that issues tickets of the given price.
  26. * Note that the price must be greater than zero, and there
  27. * are no checks to ensure this.
  28. */
  29. public TicketMachine(int ticketCost)
  30. {
  31. price = ticketCost;
  32. balance = 0;
  33. total = 0;
  34. }
  35. /**
  36. * Return the price of a ticket.
  37. */
  38. public int getPrice()
  39. {
  40. return price;
  41. }
  42. /**
  43. * Return the amount of money already inserted for the
  44. * next ticket.
  45. */
  46. public int getBalance()
  47. {
  48. return balance;
  49. }
  50. /**
  51. * Receive an amount of money in cents from a customer.
  52. */
  53. public void insertMoney(int amount)
  54. {
  55. if (amount >= 0) {
  56. balance = balance + amount;
  57. }
  58. else {
  59. System.out.println("Use a positive amount: " + amount);
  60. }
  61. }
  62. /**
  63. * Print a ticket.
  64. * Update the total collected and
  65. * reduce the balance to zero.
  66. */
  67. public void printTicket()
  68. {
  69. if (balance >= price) {
  70. // Simulate the printing of a ticket.
  71. System.out.println("##################");
  72. System.out.println("# The BlueJ Line");
  73. System.out.println("# Ticket");
  74. System.out.println("# " + price + " cents.");
  75. System.out.println("##################");
  76. System.out.println();
  77. // Update the total collected with the balance.
  78. total = total + price;
  79. // new balance
  80. balance = balance - price;
  81. }
  82. else {
  83. System.out.println("You must insert at least: " + (price - balance) + " cents.");
  84. }
  85. }
  86. //Balance life//
  87. public int refundBalance()
  88. {
  89. int amountToRefund;
  90. amountToRefund = balance;
  91. balance = 0;
  92. return amountToRefund;
  93. }
  94. }