Java version of Change

22 Change/java/src/Change.java

@@ -0,0 +1,187 @@
+import java.util.Arrays;
+import java.util.Scanner;
+
+/**
+ * Game of Change
+ * <p>
+ * Based on the Basic game of Change here
+ * https://github.com/coding-horror/basic-computer-games/blob/main/22%20Change/change.bas
+ * <p>
+ * Note:  The idea was to create a version of the 1970's Basic game in Java, without introducing
+ * new features - no additional text, error checking, etc has been added.
+ */
+public class Change {
+
+    // Used for keyboard input
+    private final Scanner kbScanner;
+
+    private enum GAME_STATE {
+        START_GAME,
+        INPUT,
+        CALCULATE,
+        END_GAME,
+        GAME_OVER
+    }
+
+    // Current game state
+    private GAME_STATE gameState;
+
+    // Amount of change needed to be given
+    private double change;
+
+    public Change() {
+        kbScanner = new Scanner(System.in);
+
+        gameState = GAME_STATE.START_GAME;
+    }
+
+    /**
+     * Main game loop
+     */
+    public void play() {
+
+        do {
+            switch (gameState) {
+                case START_GAME:
+                    intro();
+                    gameState = GAME_STATE.INPUT;
+                    break;
+
+                case INPUT:
+
+                    double costOfItem = displayTextAndGetNumber("COST OF ITEM ");
+                    double amountPaid = displayTextAndGetNumber("AMOUNT OF PAYMENT ");
+                    change = amountPaid - costOfItem;
+                    if (change == 0) {
+                        // No change needed
+                        System.out.println("CORRECT AMOUNT, THANK YOU.");
+                        gameState = GAME_STATE.END_GAME;
+                    } else if (change < 0) {
+                        System.out.println("YOU HAVE SHORT-CHANGES ME $" + (costOfItem - amountPaid));
+                        // Don't change game state so it will loop back and try again
+                    } else {
+                        // Change needed.
+                        gameState = GAME_STATE.CALCULATE;
+                    }
+                    break;
+
+                case CALCULATE:
+                    System.out.println("YOUR CHANGE, $" + change);
+                    calculateChange();
+                    gameState = GAME_STATE.END_GAME;
+                    break;
+
+                case END_GAME:
+                    System.out.println("THANK YOU, COME AGAIN");
+                    System.out.println();
+                    gameState = GAME_STATE.INPUT;
+            }
+        } while (gameState != GAME_STATE.GAME_OVER);
+    }
+
+    /**
+     * Calculate and output the change required for the purchase based on
+     * what money was paid.
+     */
+    private void calculateChange() {
+
+        double originalChange = change;
+
+        int tenDollarBills = (int) change / 10;
+        if (tenDollarBills > 0) {
+            System.out.println(tenDollarBills + " TEN DOLLAR BILL(S)");
+        }
+        change = originalChange - (tenDollarBills * 10);
+
+        int fiveDollarBills = (int) change / 5;
+        if (fiveDollarBills > 0) {
+            System.out.println(fiveDollarBills + " FIVE DOLLAR BILL(S)");
+        }
+        change = originalChange - (tenDollarBills * 10 + fiveDollarBills * 5);
+
+        int oneDollarBills = (int) change;
+        if (oneDollarBills > 0) {
+            System.out.println(oneDollarBills + " ONE DOLLAR BILL(S)");
+        }
+        change = originalChange - (tenDollarBills * 10 + fiveDollarBills * 5 + oneDollarBills);
+
+        change = change * 100;
+        double cents = change;
+
+        int halfDollars = (int) change / 50;
+        if (halfDollars > 0) {
+            System.out.println(halfDollars + " ONE HALF DOLLAR(S)");
+        }
+        change = cents - (halfDollars * 50);
+
+        int quarters = (int) change / 25;
+        if (quarters > 0) {
+            System.out.println(quarters + " QUARTER(S)");
+        }
+
+        change = cents - (halfDollars * 50 + quarters * 25);
+
+        int dimes = (int) change / 10;
+        if (dimes > 0) {
+            System.out.println(dimes + " DIME(S)");
+        }
+
+        change = cents - (halfDollars * 50 + quarters * 25 + dimes * 10);
+
+        int nickels = (int) change / 5;
+        if (nickels > 0) {
+            System.out.println(nickels + " NICKEL(S)");
+        }
+
+        change = cents - (halfDollars * 50 + quarters * 25 + dimes * 10 + nickels * 5);
+
+        int pennies = (int) (change + .5);
+        if (pennies > 0) {
+            System.out.println(pennies + " PENNY(S)");
+        }
+
+    }
+
+    private void intro() {
+        System.out.println(simulateTabs(33) + "CHANGE");
+        System.out.println(simulateTabs(15) + "CREATIVE COMPUTING  MORRISTOWN, NEW JERSEY");
+        System.out.println();
+        System.out.println("I, YOUR FRIENDLY MICROCOMPUTER, WILL DETERMINE");
+        System.out.println("THE CORRECT CHANGE FOR ITEMS COSTING UP TO $100.");
+        System.out.println();
+    }
+
+    /*
+     * Print a message on the screen, then accept input from Keyboard.
+     * Converts input to Integer
+     *
+     * @param text message to be displayed on screen.
+     * @return what was typed by the player.
+     */
+    private double displayTextAndGetNumber(String text) {
+        return Double.parseDouble(displayTextAndGetInput(text));
+    }
+
+    /*
+     * Print a message on the screen, then accept input from Keyboard.
+     *
+     * @param text message to be displayed on screen.
+     * @return what was typed by the player.
+     */
+    private String displayTextAndGetInput(String text) {
+        System.out.print(text);
+        return kbScanner.next();
+    }
+
+    /**
+     * Simulate the old basic tab(xx) command which indented text by xx spaces.
+     *
+     * @param spaces number of spaces required
+     * @return String with number of spaces
+     */
+    private String simulateTabs(int spaces) {
+        char[] spacesTemp = new char[spaces];
+        Arrays.fill(spacesTemp, ' ');
+        return new String(spacesTemp);
+    }
+}

22 Change/java/src/ChangeGame.java

@@ -0,0 +1,6 @@
+public class ChangeGame {
+    public static void main(String[] args) {
+        Change change = new Change();
+        change.play();
+    }
+}