1    /* 
2     *Program featuring an array to store and interactively manipulate a list of numbers. 
3     */
4    
5    package arrayplay;
6    
7    import shapes.SSquare;
8    
9    import javax.swing.*;
10   import java.awt.*;
11   import java.io.File;
12   import java.io.FileNotFoundException;
13   import java.util.Scanner;
14   
15   public class NumberList {
16       // VARIABLES LOCAL TO THE CLASS, AND HENCE GLOBAL TO THE METHODS
17       private static final int LIMIT = 1000;
18       private static int[] numbers = new int[LIMIT];
19       private static int numberOfNumbers = 0;
20       private static Scanner commandReader = new Scanner(System.in);
21   
22       public static void main(String[] args) {
23           try {
24               // ESTABLISH THE ARRAY OF NUMBERS
25               readNumbers();
26               // CHECK THE DATA
27               // System.out.println("nThe original list of numbers ...");
28               // displayNumbers();
29               // ENTER THE INTERPRETER
30               interpreter();
31           } catch (FileNotFoundException ex) {
32               System.out.println("The file was not found. Please think again.");
33               System.exit(-1);
34           }
35       }
36   
37       // Assuming that the data file will be found in the public_html/data
38       // subdirectory of the user’s home directory.
39       private static Scanner establishScanner(String fn) throws FileNotFoundException{
40           String separator = File.separator;
41           String homeDirectory = System.getProperty("user.home");
42           String path = homeDirectory + separator + "public_html" + separator + "data" + separator;
43           String fullFileName = path + fn ;
44           return new Scanner(new File(fullFileName));
45       }
46   
47       private static void readNumbers()throws FileNotFoundException{
48           Scanner scanner = establishScanner("NumberSet.txt");
49           while (scanner.hasNext()){
50               numbers[numberOfNumbers] = scanner.nextInt();
51               numberOfNumbers = numberOfNumbers + 1;
52           }
53       }
54   
55       private static void displayNumbers(){
56           for (int x = 0; x < numberOfNumbers; x=x+1){
57               System.out.println(numbers[x]);
58           }
59       }
60   
61       private static void interpreter() {
62           System.out.print(">>> ");
63           String command =commandReader.next();
64           if(command.equalsIgnoreCase("display")){
65               interpreterDisplayCommand();
66           }else if (command.equalsIgnoreCase("print")){
67               interpretPrintCommand();
68           }else if (command.equalsIgnoreCase("swap")){
69               interpretSwapCommand();
70           }else if (command.equalsIgnoreCase("add")){
71               interpretAddCommand();
72           }else if (command.equalsIgnoreCase("help")){
73               interpretHelpCommand();
74           }else if (command.equalsIgnoreCase("exit")){
75               System.exit(0);
76           }else {
77               System.out.println("### Unrecognizable command" + command);
78           }
79           interpreter();
80       }
81       private static void interpreterDisplayCommand(){
82           displayNumbers();
83       }
84       private static void interpretPrintCommand(){
85           String operand = commandReader.next();
86           if(operand.equalsIgnoreCase("first")){
87               System.out.println(numbers[0]);
88           }else if (operand.equalsIgnoreCase("last")){
89               System.out.println(numbers[numberOfNumbers - 1]);
90           }else {
91               int index = Integer.valueOf(operand);
92               System.out.println(numbers[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          int temp = numbers[position1 - 1];
109          numbers[position1 - 1] = numbers[position2-1];
110          numbers[position2 - 1] = temp;
111  
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          numberOfNumbers = numberOfNumbers + 1;
124      }
125      private static void addLast(){
126          numbers[numberOfNumbers] = commandReader.nextInt();
127      }
128      private static void addFirst(){
129          for (int x = numberOfNumbers; x > 0; x=x-1){
130              numbers[x] = numbers[x-1];
131          }
132          numbers[0] = commandReader.nextInt();
133      }
134  }
135