Connecting Tech Pros Worldwide Forums | Help | Site Map
bytes > topic > java > answers

Please help!! I'm stuck with java code...API not helping.

Newbie
  
Join Date: Sep 2008
Posts: 2
#1: Sep 17 '08
hi, I'm working on an exercise, i did a lot of work already and i just can't figure where I'm going wrong, this is what I'm trying to achieve

Sample IO
************************************************** *****************************
Expand|Select|Wrap|Line Numbers
  1. Welcome to PeopleSoft 2
  2. MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
  3. a
  4. Enter the student number
  5. MSXMIC001
  6. Enter the name
  7. Mickey Mouse
  8. Done
  9. MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
  10. a
  11. Enter the student number
  12. CHPALV001
  13. Enter the name
  14. Alvin the Chipmunk
  15. Done
  16. MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
  17. a
  18. Enter the student number
  19. DCKDON002
  20. Enter the name
  21. Donald Duck
  22. Done
  23. MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
  24. l
  25. Student: DCKDON002, Donald Duck
  26. Student: CHPALV001, Alvin the Chipmunk
  27. Student: MSXMIC001, Mickey Mouse
  28. Done
  29. MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
  30. s
  31. Done
  32. MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
  33. l
  34. Student: CHPALV001, Alvin the Chipmunk
  35. Student: DCKDON002, Donald Duck
  36. Student: MSXMIC001, Mickey Mouse
  37. Done
  38. MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
  39. d
  40. Enter the student number
  41. DCKDON002
  42. Done
  43. MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
  44. l
  45. Student: CHPALV001, Alvin the Chipmunk
  46. Student: MSXMIC001, Mickey Mouse
  47. Done
  48. MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
  49. x
************************************************** *************
and this is my code so far, that won't work....
************************************************** *****************************************
Expand|Select|Wrap|Line Numbers
  1. import java.util.NoSuchElementException;
  2. import java.util.Scanner;
  3.  
  4. public class LinkedList2
  5. {    private class Node
  6.     {
  7.             private String name;
  8.             private String stuName;
  9.             private Node link;
  10.  
  11.  
  12.     public Node()
  13.     {
  14.         link = null;
  15.         name = null;
  16.         stuName = null;
  17.     }
  18.  
  19.     public Node(String newStuName, String newName, Node linkValue)
  20.     {
  21.         setData(newStuName, newName);
  22.         link = linkValue;
  23.     }
  24.     public void setData(String newStuName, String newName)
  25.     {
  26.         name = newName;
  27.         stuName = newStuName;
  28.     }
  29.     public void setLink(Node newLink)
  30.     {
  31.         link = newLink;
  32.     }
  33.     public String getStuName()
  34.     {
  35.         return stuName;
  36.     }
  37.     public String getName()
  38.     {
  39.         return name;
  40.     }
  41.     public Node getLink()
  42.     {
  43.         return link;
  44.     }
  45.     }//end of node inner class
  46.  
  47.     public class List2Iterator//inner class for iterators for linkedlist2
  48.     {    
  49.         private Node position;
  50.         private Node previous;
  51.  
  52.         public List2Iterator()
  53.         {
  54.             position = head;
  55.             previous = null;
  56.         }
  57.         public void restart()
  58.         {
  59.             position = head;
  60.             previous = null;
  61.         }
  62.         public String next()
  63.         {
  64.             if(!hasNext())
  65.                 throw new NoSuchElementException();
  66.             String toReturn = position.stuName;
  67.             previous = position;
  68.             position = position.link;
  69.             return toReturn;
  70.         }
  71.         public boolean hasNext()
  72.         {
  73.             return(position != null);
  74.         }
  75.         public String peek()
  76.         {
  77.             if(!hasNext())
  78.                 throw new IllegalStateException();
  79.                 return position.stuName;
  80.         }
  81.         public void addHare(String newData)
  82.         {
  83.             if(position == null && previous != null)//if at end o list
  84.  
  85.             previous.link = new Node(newData, null);
  86.             else if(position == null || previous == null)
  87.             LinkedList2.this.addToStart(newData);
  88.  
  89.             else{
  90.                 Node temp = new Node(newData, position);
  91.                 previous.link = temp;
  92.                 previous = temp;
  93.             }
  94.         }
  95.         public void changeHare(String newData)
  96.         {
  97.             if(position == null)
  98.                 throw new IllegalStateException();
  99.                 else
  100.                 position.stuName = newData;
  101.         }
  102.         public void delete()
  103.         {
  104.             if(position == null)
  105.                 throw new IllegalStateException();
  106.                 else if(previous == null)
  107.                 {
  108.                     head = head.link;
  109.                     position = head;
  110.                 }
  111.                 else
  112.                 {
  113.                     previous.link = position.link;
  114.                     position = position.link;
  115.                 }
  116.         }
  117.     }
  118.         private Node head;
  119.  
  120.         public List2Iterator iterator()
  121.         {
  122.             return new List2Iterator();
  123.         }
  124.         public LinkedList2()
  125.         {
  126.             head = null;//adds node at the stat of the list with the specified data
  127.         }
  128.         public void addToStart(String itemStuName, String itemName)
  129.         {
  130.         head = new Node1(itemStuName, itemName, head);
  131.         }
  132.         }
  133.         public boolean deleteHeadNode()
  134.         {
  135.             if(head != null){
  136.  
  137.                 head = head.link;
  138.                 return true;
  139.             }
  140.             else 
  141.             return false;
  142.         }
  143.         /*public int size()//return number of nodes in the list
  144.         {
  145.             int count = 0;
  146.             Node position = head;
  147.             while(position != null)
  148.             {
  149.                 count++;
  150.                 position = position.link;
  151.             }
  152.             return count;
  153.         }*/
  154.         public boolean contains(String stuName, String name)
  155.         {
  156.         return (find(stuName, name) != null); 
  157.         }
  158.         private Node find(String target)
  159.         {
  160.             Node position = head;
  161.             String itemAtPosition;
  162.             while (position != null)
  163.             {
  164.                 itemAtPosition = position.stuName;
  165.                 if(itemAtPosition.equals(target))
  166.                     return position;
  167.                     position = position.link;
  168.             }
  169.             return null; //target wan not found
  170.         }
  171.         public void outPutList()
  172.         {
  173.             Node position = head;
  174.             while(position != null);
  175.             {
  176.                 System.out.println(position.stuName);
  177.                 position = position.link;
  178.             }
  179.         }
  180.         public boolean isEmpty()
  181.         {
  182.             return(head == null);
  183.         }
  184.         public void clear()
  185.         {
  186.             head = null;
  187.         }
  188.         public boolean equals(Object otherObject)
  189.         {
  190.             if(otherObject == null)
  191.                 return false;
  192.                 else if(getClass() != otherObject.getClass())
  193.                     return false;
  194.                 else{
  195.                     LinkedList2 otherList = (LinkedList2)otherObject;
  196.                     if(size() != otherList.size())
  197.                         return false;
  198.                         Node position = head;
  199.                         Node otherPosition = otherList.head;
  200.                         while(position != null)
  201.                         {    
  202.                             if((!(position.item.equals(otherPosition.stuName))))
  203.                                 return false;
  204.                             position = position.link;
  205.                             otherPosition = otherPosition.link;
  206.                         }
  207.                         return true;//a mis match was not found
  208.                     }
  209.         }
  210.  
  211.  
  212.         public static void main(String[] args)
  213.         {
  214.             Scanner keyboard = new Scanner(System.in);
  215.  
  216.             LinkedList2 list = new LinkedList2();
  217.             LinkedList2.List2Iterator i = list.iterator();
  218.  
  219.             System.out.println("Welcome to PeopleSoft 2");
  220.  
  221.             int choice = keyboard.nextInt();
  222.             while(choice !== 5)
  223.             {
  224.                 System.out.println("MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it");            
  225.                 switch(choice)
  226.                 {
  227.                     case 1:
  228.                     System.out.println("Enter the student number");
  229.                     stuNum = keyboard.next();
  230.                     System.out.println("Enter the Student name");
  231.                     name = keyboard.next();
  232.                     list.addToStart(studentNum,name);
  233.                     System.out.println("Done");
  234.                     break;
  235.  
  236.                     case 2:
  237.                     System.out.println("Enter student number");
  238.                     stuName = keyboard.next();
  239.                     i.restart();
  240.                     i.next();
  241.                     System.out.println("Will delete the node for; " + i.peek());
  242.                     i.delete();
  243.                     System.out.println("Done");
  244.                     break;
  245.  
  246.                     case 3:
  247.                     System.out.println("list now contains:");
  248.                     i.restart();
  249.                     while(i.hasNext())
  250.                     System.out.println("Student: " + i.next());
  251.                     System.out.println();
  252.                     System.out.println("Done");
  253.                     break;
  254.  
  255.                     case 5:
  256.                     System.exit(0);
  257.                     break;
  258.  
  259.                     default:
  260.                     System.out.println("Error,please check your input again");
  261.                     break;    
  262.                 }
  263.             }        
  264.  
  265.  
  266.  
  267.         }
  268.  
  269.  
  270. }
************************************************** ******************************************
please help me see where I'm going wrong.

JosAH's Avatar
Expert
  
Join Date: Mar 2007
Posts: 10,611
#2: Sep 17 '08

re: Please help!! I'm stuck with java code...API not helping.

Quote:

Originally Posted by BlueroY

and this is my code so far, that won't work....

What doesn't work? We are not going to do your homework for you but we're
willing to help you to solve any problem; please help us to help you and specify
what doesn't actually work.

kind regards,

Jos
Newbie
  
Join Date: Sep 2008
Posts: 2
#3: Sep 17 '08

re: Please help!! I'm stuck with java code...API not helping.

hi again, sorry I did not give enough information,
when i compile, I get about 70 lines of errors saying "enum expected" what i really have trouble with is letting the user enter all the information. I'm also having trouble writing a suitable delete() method....the one in my code is from my textbook example, actualy almost of all the code...all I really need is how do let the user enter all the data and do I need an array for (studentNumber and name)?..I'm a bit frustrated now.
JosAH's Avatar
Expert
  
Join Date: Mar 2007
Posts: 10,611
#4: Sep 17 '08

re: Please help!! I'm stuck with java code...API not helping.

If your program doesn't compile you definitely can't run it. Can you show us the
first compiler error diagnostic? (copied verbatim, including the offending line number).

kind regards,

Jos
Reply

« previous question | next question »

/bytes/development

/bytes/it

Forums
Visit our community forums for general discussions and latest on Bytes

Our staff and community areas have moved to bytes.com/forums/

/bytes/about

We are a network of experts and professionals in IT and software development that help one another with answers to tough questions and share insights. Get the best answers to your questions from over 226,510 network members.

dev questions:
algorithms | asp | asp.net | c/c++ | coldfusion | c# | flash | html/css | java | javascript |
mobile dev | .net | perl | php | python | ruby | software dev | vb.net | visual basic | xml
it questions:
access | apache | careers | db2 | iis | macosx | mysql | networking | oracle | postgresql | sql server | unix | windows

About Bytes | Copyright 1995-2009 BYTES. All rights Reserved