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Sep 17th, 2008
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Please with homework...did alot of work already and I'm stuck

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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
*******************************************************************************
Welcome to PeopleSoft 2
MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
a
Enter the student number
MSXMIC001
Enter the name
Mickey Mouse
Done
MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
a
Enter the student number
CHPALV001
Enter the name
Alvin the Chipmunk
Done
MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
a
Enter the student number
DCKDON002
Enter the name
Donald Duck
Done
MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
l
Student: DCKDON002, Donald Duck
Student: CHPALV001, Alvin the Chipmunk
Student: MSXMIC001, Mickey Mouse
Done
MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
s
Done
MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
l
Student: CHPALV001, Alvin the Chipmunk
Student: DCKDON002, Donald Duck
Student: MSXMIC001, Mickey Mouse
Done
MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
d
Enter the student number
DCKDON002
Done
MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
l
Student: CHPALV001, Alvin the Chipmunk
Student: MSXMIC001, Mickey Mouse
Done
MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it
x
***************************************************************
and this is my code so far, that won't work....
*******************************************************************************************
import java.util.NoSuchElementException;
import java.util.Scanner;

public class LinkedList2
{ private class Node
{
private String name;
private String stuName;
private Node link;


public Node()
{
link = null;
name = null;
stuName = null;
}

public Node(String newStuName, String newName, Node linkValue)
{
setData(newStuName, newName);
link = linkValue;
}
public void setData(String newStuName, String newName)
{
name = newName;
stuName = newStuName;
}
public void setLink(Node newLink)
{
link = newLink;
}
public String getStuName()
{
return stuName;
}
public String getName()
{
return name;
}
public Node getLink()
{
return link;
}
}//end of node inner class

public class List2Iterator//inner class for iterators for linkedlist2
{
private Node position;
private Node previous;

public List2Iterator()
{
position = head;
previous = null;
}
public void restart()
{
position = head;
previous = null;
}
public String next()
{
if(!hasNext())
throw new NoSuchElementException();
String toReturn = position.stuName;
previous = position;
position = position.link;
return toReturn;
}
public boolean hasNext()
{
return(position != null);
}
public String peek()
{
if(!hasNext())
throw new IllegalStateException();
return position.stuName;
}
public void addHare(String newData)
{
if(position == null && previous != null)//if at end o list

previous.link = new Node(newData, null);
else if(position == null || previous == null)
LinkedList2.this.addToStart(newData);

else{
Node temp = new Node(newData, position);
previous.link = temp;
previous = temp;
}
}
public void changeHare(String newData)
{
if(position == null)
throw new IllegalStateException();
else
position.stuName = newData;
}
public void delete()
{
if(position == null)
throw new IllegalStateException();
else if(previous == null)
{
head = head.link;
position = head;
}
else
{
previous.link = position.link;
position = position.link;
}
}
}
private Node head;

public List2Iterator iterator()
{
return new List2Iterator();
}
public LinkedList2()
{
head = null;//adds node at the stat of the list with the specified data
}
public void addToStart(String itemStuName, String itemName)
{
head = new Node1(itemStuName, itemName, head);
}
}
public boolean deleteHeadNode()
{
if(head != null){

head = head.link;
return true;
}
else
return false;
}
/*public int size()//return number of nodes in the list
{
int count = 0;
Node position = head;
while(position != null)
{
count++;
position = position.link;
}
return count;
}*/
public boolean contains(String stuName, String name)
{
return (find(stuName, name) != null);
}
private Node find(String target)
{
Node position = head;
String itemAtPosition;
while (position != null)
{
itemAtPosition = position.stuName;
if(itemAtPosition.equals(target))
return position;
position = position.link;
}
return null; //target wan not found
}
public void outPutList()
{
Node position = head;
while(position != null);
{
System.out.println(position.stuName);
position = position.link;
}
}
public boolean isEmpty()
{
return(head == null);
}
public void clear()
{
head = null;
}
public boolean equals(Object otherObject)
{
if(otherObject == null)
return false;
else if(getClass() != otherObject.getClass())
return false;
else{
LinkedList2 otherList = (LinkedList2)otherObject;
if(size() != otherList.size())
return false;
Node position = head;
Node otherPosition = otherList.head;
while(position != null)
{
if((!(position.item.equals(otherPosition.stuName))))
return false;
position = position.link;
otherPosition = otherPosition.link;
}
return true;//a mis match was not found
}
}


public static void main(String[] args)
{
Scanner keyboard = new Scanner(System.in);

LinkedList2 list = new LinkedList2();
LinkedList2.List2Iterator i = list.iterator();

System.out.println("Welcome to PeopleSoft 2");

int choice = keyboard.nextInt();
while(choice !== 5)
{
System.out.println("MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it");
switch(choice)
{
case 1:
System.out.println("Enter the student number");
stuNum = keyboard.next();
System.out.println("Enter the Student name");
name = keyboard.next();
list.addToStart(studentNum,name);
System.out.println("Done");
break;

case 2:
System.out.println("Enter student number");
stuName = keyboard.next();
i.restart();
i.next();
System.out.println("Will delete the node for; " + i.peek());
i.delete();
System.out.println("Done");
break;

case 3:
System.out.println("list now contains:");
i.restart();
while(i.hasNext())
System.out.println("Student: " + i.next());
System.out.println();
System.out.println("Done");
break;

case 5:
System.exit(0);
break;

default:
System.out.println("Error,please check your input again");
break;
}
}



}


}
********************************************************************************************
please help me see where I'm going wrong.
Similar Threads
Reputation Points: 10
Solved Threads: 0
Newbie Poster
brain damaged is offline Offline
2 posts
since Sep 2008
Sep 17th, 2008
0

Re: Please with homework...did alot of work already and I'm stuck

tons of unformatted code, no description of what "goes wrong", no nothing.
You'll have to do better than that if you expect us to fix the code you pulled from some other website for you, kid.
Team Colleague
Reputation Points: 1658
Solved Threads: 331
duckman
jwenting is offline Offline
7,719 posts
since Nov 2004
Sep 17th, 2008
0

Re: Please with homework...did alot of work already and I'm stuck

could you put the code between [ CODE] [ /CODE] tags to make it more readable and also give the errors you are getting? might make it a lot easier to actually help you out with this one
Reputation Points: 919
Solved Threads: 354
Nearly a Posting Maven
stultuske is offline Offline
2,487 posts
since Jan 2007
Sep 17th, 2008
0

Re: Please with homework...did alot of work already and I'm stuck

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.
[import java.util.NoSuchElementException;
import java.util.Scanner;

public class LinkedList2
{ private class Node
{
private String name;
private String stuName;
private Node link;


public Node()
{
link = null;
name = null;
stuName = null;
}

public Node(String newStuName, String newName, Node linkValue)
{
setData(newStuName, newName);
link = linkValue;
}
public void setData(String newStuName, String newName)
{
name = newName;
stuName = newStuName;
}
public void setLink(Node newLink)
{
link = newLink;
}
public String getStuName()
{
return stuName;
}
public String getName()
{
return name;
}
public Node getLink()
{
return link;
}
}//end of node inner class

public class List2Iterator//inner class for iterators for linkedlist2
{
private Node position;
private Node previous;

public List2Iterator()
{
position = head;
previous = null;
}
public void restart()
{
position = head;
previous = null;
}
public String next()
{
if(!hasNext())
throw new NoSuchElementException();
String toReturn = position.stuName;
previous = position;
position = position.link;
return toReturn;
}
public boolean hasNext()
{
return(position != null);
}
public String peek()
{
if(!hasNext())
throw new IllegalStateException();
return position.stuName;
}
public void addHare(String newData)
{
if(position == null && previous != null)//if at end o list

previous.link = new Node(newData, null);
else if(position == null || previous == null)
LinkedList2.this.addToStart(newData);

else{
Node temp = new Node(newData, position);
previous.link = temp;
previous = temp;
}
}
public void changeHare(String newData)
{
if(position == null)
throw new IllegalStateException();
else
position.stuName = newData;
}
public void delete()
{
if(position == null)
throw new IllegalStateException();
else if(previous == null)
{
head = head.link;
position = head;
}
else
{
previous.link = position.link;
position = position.link;
}
}
}
private Node head;

public List2Iterator iterator()
{
return new List2Iterator();
}
public LinkedList2()
{
head = null;//adds node at the stat of the list with the specified data
}
public void addToStart(String itemStuName, String itemName)
{
head = new Node1(itemStuName, itemName, head);
}
}
public boolean deleteHeadNode()
{
if(head != null){

head = head.link;
return true;
}
else
return false;
}
/*public int size()//return number of nodes in the list
{
int count = 0;
Node position = head;
while(position != null)
{
count++;
position = position.link;
}
return count;
}*/
public boolean contains(String stuName, String name)
{
return (find(stuName, name) != null);
}
private Node find(String target)
{
Node position = head;
String itemAtPosition;
while (position != null)
{
itemAtPosition = position.stuName;
if(itemAtPosition.equals(target))
return position;
position = position.link;
}
return null; //target wan not found
}
public void outPutList()
{
Node position = head;
while(position != null);
{
System.out.println(position.stuName);
position = position.link;
}
}
public boolean isEmpty()
{
return(head == null);
}
public void clear()
{
head = null;
}
public boolean equals(Object otherObject)
{
if(otherObject == null)
return false;
else if(getClass() != otherObject.getClass())
return false;
else{
LinkedList2 otherList = (LinkedList2)otherObject;
if(size() != otherList.size())
return false;
Node position = head;
Node otherPosition = otherList.head;
while(position != null)
{
if((!(position.item.equals(otherPosition.stuName))))
return false;
position = position.link;
otherPosition = otherPosition.link;
}
return true;//a mis match was not found
}
}


public static void main(String[] args)
{
Scanner keyboard = new Scanner(System.in);

LinkedList2 list = new LinkedList2();
LinkedList2.List2Iterator i = list.iterator();

System.out.println("Welcome to PeopleSoft 2");

int choice = keyboard.nextInt();
while(choice !== 5)
{
System.out.println("MENU: (A)dd student, (D)elete, (L)ist, (S)ort, e(X)it");
switch(choice)
{
case 1:
System.out.println("Enter the student number");
stuNum = keyboard.next();
System.out.println("Enter the Student name");
name = keyboard.next();
list.addToStart(studentNum,name);
System.out.println("Done");
break;

case 2:
System.out.println("Enter student number");
stuName = keyboard.next();
i.restart();
i.next();
System.out.println("Will delete the node for; " + i.peek());
i.delete();
System.out.println("Done");
break;

case 3:
System.out.println("list now contains:");
i.restart();
while(i.hasNext())
System.out.println("Student: " + i.next());
System.out.println();
System.out.println("Done");
break;

case 5:
System.exit(0);
break;

default:
System.out.println("Error,please check your input again");
break;
}
}
]
Last edited by brain damaged; Sep 17th, 2008 at 4:15 pm. Reason: forgot to add code in tags
Reputation Points: 10
Solved Threads: 0
Newbie Poster
brain damaged is offline Offline
2 posts
since Sep 2008
Sep 17th, 2008
0

Re: Please with homework...did alot of work already and I'm stuck

more unformatted code...
And those error messages are quite clear. Learn to interpret them.
Team Colleague
Reputation Points: 1658
Solved Threads: 331
duckman
jwenting is offline Offline
7,719 posts
since Nov 2004

This thread is more than three months old

No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.
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