package arrayplay; import java.io.File; import java.io.FileNotFoundException; import java.util.Scanner; public class NumberList<numberOfNumbers, numbers> { /** * 19 * @param args the command line arguments * 20 */ // VARIALBES LOCAL TO THE CLASS, AND HENCE GLOBAL TO THE METHODS private static final int LIMIT = 1000; private static int[] numbers = new int[LIMIT]; private static int numberOfNumbers = 0; private static Scanner commandReader = new Scanner(System.in); /** * @param args the command line arguments */ public static void main(String[] args) { try { //ESTABLIS ARRAY OF NUMBERS readNumbers(); // CHECK THE DATA //System.out.println("\nThe original list of numbers ..."); //displayNumbers(); //ENTER THE INTERPRETER interpreter(); } catch (FileNotFoundException ex) { System.out.println("The file was not found. Please think again."); System.exit(-1); } } // Assuming that the data file will be found in the public_html/data // subdirectory of the user's home directory private static Scanner establishScanner(String fn) throws FileNotFoundException { String separator = System.getProperty("file.separator"); String homeDirectory = System.getProperty("user.home"); String path = homeDirectory + separator + "CS1Files" + separator + "data" + separator; String fullFileName = path + fn; return new Scanner(new File(fullFileName)); } private static void readNumbers() throws FileNotFoundException { Scanner scanner = establishScanner("NumberSet.txt"); while (scanner.hasNext()) { numbers[numberOfNumbers] = scanner.nextInt(); numberOfNumbers = numberOfNumbers + 1; } } private static void displayNumbers() { for (int x = 0; x < numberOfNumbers; x = x + 1) { System.out.println(numbers[x]); } } private static void interpreter() { System.out.print(">>>"); String command = commandReader.next(); if (command.equalsIgnoreCase("DISPLAY")) { interpreterDisplayCommand(); } else if (command.equalsIgnoreCase("PRINT")) { interpreterPrintCommand(); } else if (command.equalsIgnoreCase("SWAP")) { interpreterSwapCommand(); } else if (command.equalsIgnoreCase("ADD")) { interpreterAddCommand(); } else if (command.equalsIgnoreCase("HELP")) { interpreterHelpCommand(); } else if (command.equalsIgnoreCase("EXIT")) { System.exit(0); } else { System.out.println("### Unrecognizable command: " + command); } System.out.print("\n"); interpreter(); } private static void interpreterDisplayCommand() { displayNumbers(); } private static void interpreterPrintCommand() { String operand = commandReader.next(); if (operand.equalsIgnoreCase("FIRST")) { System.out.println(numbers[0]); } else if (operand.equalsIgnoreCase("LAST")) { System.out.println(numbers[numberOfNumbers - 1]); } else { int index = Integer.valueOf(operand); System.out.println(numbers[index - 1]); } } private static void interpreterSwapCommand() { int position1 = commandReader.nextInt(); int position2 = commandReader.nextInt(); int temp = numbers[position1 - 1]; numbers[position1 - 1] = numbers[position2 - 1]; numbers[position2 - 1] = temp; } private static void interpreterAddCommand() { String position = commandReader.next(); if (position.equalsIgnoreCase("Last")) { addLast(); } else if (position.equalsIgnoreCase("FIRST")) { addFirst(); } else { System.out.println("### invalid operand for add command"); } numberOfNumbers = numberOfNumbers + 1; } private static void interpreterHelpCommand() { System.out.println("HELP - display menu of commands"); System.out.println("DISPLAY - display the list of numbers"); System.out.println("PRINT - print a number (FIRST; LAST; nth)"); System.out.println("SWAP - exchange two elements (nth; mth)"); System.out.println("ADD - add a number to the list (FIRST; LAST)"); System.out.println("EXIT - terminate execution of the program"); } private static void addLast() { numbers[numberOfNumbers] = commandReader.nextInt(); } { numbers[numberOfNumbers]=commandReader.nextInt(); } private static void addFirst() { for (int x = numberOfNumbers; x > 0; x = x - 1) { numbers[x] = numbers[x - 1]; } numbers[0] = commandReader.nextInt(); } }