1    
2    /* 
3     * Program featuring an array to store and interactively manipulate a list of numbers. 
4     */
5    package arrayplay;
6    
7    import java.io.File;
8    import java.io.FileNotFoundException;
9    import java.util.Scanner;
10   
11   public class WordList {
12       // VARIABLES LOCAL TO THE CLASS, AND HENCE GLOBAL TO THE METHODS
13       private static final int LIMIT = 1000;
14       private static String[] words = new String[LIMIT];
15       private static int numberOfWords = 0;
16       private static Scanner commandReader = new Scanner(System.in);
17   
18       public static void main(String[] args) {
19           try {
20               // ESTABLISH THE ARRAY OF NUMBERS
21               readNumbers();
22               // CHECK THE DATA
23               // System.out.println("nThe original list of numbers ...");
24               // displayNumbers();
25               // ENTER THE INTERPRETER
26               interpreter();
27           } catch (FileNotFoundException ex) {
28               System.out.println("The file was not found. Please think again.");
29               System.exit(-1);
30           }
31       }
32   
33       // Assuming that the data file will be found in the public_html/data
34       // subdirectory of the user’s home directory.
35       private static Scanner establishScanner(String fn) throws FileNotFoundException {
36           String separator = File.separator;
37           String homeDirectory = System.getProperty("user.home");
38   //        System.out.println(homeDirectory);
39           String path = homeDirectory + separator + "public_html" + separator + "data" + separator;
40           String fullFileName = path + fn;
41           return new Scanner(new File(fullFileName));
42       }
43   
44       private static void readNumbers() throws FileNotFoundException {
45           Scanner scanner = establishScanner("WordSet.txt");
46           while (scanner.hasNext()) {
47               //Get rid of int the reads as a string
48               words[numberOfWords] = scanner.next();
49               numberOfWords = numberOfWords + 1;
50           }
51       }
52   
53       private static void displayNumbers() {
54           for (int x = 0; x < numberOfWords; x = x + 1) {
55               System.out.println(words[x]);
56           }
57       }
58   
59       private static void interpreter() {
60           System.out.print(">>> ");
61           String command = commandReader.next();
62           if (command.equalsIgnoreCase("DISPLAY")) {
63               interpreterDisplayCommand();
64           } else if (command.equalsIgnoreCase("PRINT")) {
65               interpretPrintCommand();
66           } else if (command.equalsIgnoreCase("SWAP")) {
67               interpretSwapCommand();
68           } else if (command.equalsIgnoreCase("ADD")) {
69               interpretAddCommand();
70           } else if (command.equalsIgnoreCase("HELP")) {
71               interpretHelpCommand();
72           } else if (command.equalsIgnoreCase("EXIT")) {
73               System.exit(0);
74           } else {
75               System.out.println("### Unrecognizable command: " + command);
76           }
77           interpreter();
78       }
79   
80       private static void interpreterDisplayCommand() {
81           displayNumbers();
82       }
83   
84       private static void interpretPrintCommand() {
85           String operand = commandReader.next();
86           if (operand.equalsIgnoreCase("FIRST")) {
87               System.out.println(words[0]);
88           } else if (operand.equalsIgnoreCase("LAST")) {
89               System.out.println(words[numberOfWords - 1]);
90           } else {
91               int index = Integer.valueOf(operand);
92               System.out.println(words[index - 1]);
93           }
94       }
95   
96       private static void interpretHelpCommand() {
97           System.out.println("HELP - display a menu of commands");
98           System.out.println("DISPLAY - display the list of numbers");
99           System.out.println("PRINT - print a number (FIRST;LAST;nth)");
100          System.out.println("SWAP - exchange two elements (nth;mth)");
101          System.out.println("ADD - add a number to the list (FIRST;LAST)");
102          System.out.println("EXIT - terminate execution of the program");
103      }
104  
105      private static void interpretSwapCommand() {
106          int position1 = commandReader.nextInt();
107          int position2 = commandReader.nextInt();
108          //
109          String temp = words[position1 - 1];
110          words[position1 - 1] = words[position2 - 1];
111          words[position2 - 1] = temp;
112      }
113  
114      private static void interpretAddCommand() {
115          String position = commandReader.next();
116          if (position.equalsIgnoreCase("LAST")) {
117              addLast();
118          } else if (position.equalsIgnoreCase("FIRST")) {
119              addFirst();
120          } else {
121              System.out.println("### invalid operand for add command");
122          }
123          numberOfWords = numberOfWords + 1;
124      }
125      //adding what the command reader sees to the end of the last position  array
126      private static void addLast() {
127          // numberOfWords is a counter
128          words[numberOfWords] = commandReader.next();
129      }
130  
131      private static void addFirst() {
132          for (int x = numberOfWords; x > 0; x = x - 1) {
133              words[x] = words[x - 1];
134          }
135          words[0] = commandReader.next();
136      }
137  }
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