Java Linked List

Code:

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public class GuestListNode
{
  private String name;
  private int numGuests;
  private GuestListNode next;
 
  public GuestListNode(String name, int numGuests)
  {
    this.name = name;
    this.numGuests = numGuests;
  }
 
  public String getName()
  {
    return name;
  }
 
  public int getNumGuests()
  {
    return numGuests;
  }
 
  public void setNumGuests(int n)
  {
    numGuests = n;
  }
 
  public GuestListNode getNext()
  {
    return next;
  }
 
  public void setNext(GuestListNode next)
  {
    this.next = next;
  }
}

public class GuestList
{
  private GuestListNode head;
 
  public GuestList()
  {
    head = null;
  }
 
  public void addGuest(String name, int numGuests)
  {
    head = new GuestListNode(name, numGuests);
  }


 
  public String toString()
  {
    while(head != null)
    {
      System.out.println(head.getName() + " " + head.getNumGuests());
      head = head.getNext();
    }
    String s = "";
    return s;
  } 
 
 
  public static void main(String[] args)
  {
    GuestList gl = new GuestList();
    gl.addGuest("Calypso", 1);
    gl.addGuest("Odysseus", 10);
    gl.addGuest("Penelope", 117);
    gl.addGuest("Athena", 2);
    gl.addGuest("Helios", 1);
    gl.addGuest("Cyclops", 5);
    //gl.removeGuest("Cyclops");
    System.out.print(gl);
  }
}

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Right now when I hit run in GuestList, the result it:
Cyclops 5
How do I make it so all the guests are printed out.

I don't know for sure, but maybe you should use an iterator and print each line separate.

Quote:

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Originally Posted by nomss

Right now when I hit run in GuestList, the result it:
Cyclops 5
How do I make it so all the guests are printed out.

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First correct your 'addGuest( ... )' method; as it is now it simply creates a node, makes 'head' refer to it and forgets about all the other nodes already in the list. I guess the assignment doesn't allow you to use a standard List?

kind regards,

Jos

the problem is with your addGuest() method, not your toString.

I would alter it so you pass the constuctor the current head node.

Code:

---

public void addGuest(String name, int numGuests) {
    head = new GuestListNode(head, name, numGuests);
}

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Also, toString() methods should generally not use a println anywhere - thats not their purpose.
It should do something like this:

Code:

---

public String toString() {
  GuestListNode temp = head;
  String s = "";
    while(temp != null){
        s += temp.getName() + " " + temp.getNumGuests() + "\n";
        temp = temp.getNext();
    }
    return s;
}

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Quote:

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Originally Posted by berkeleybross

the problem is with your addGuest() method, not your toString.
I understand that when addGuest() is called it only makes new nodes but doesn't point to the next new node that is created. I don't really know how to go about doing this.
I would alter it so you pass the constuctor the current head node.

Code:

---

public void addGuest(String name, int numGuests) {
    head = new GuestListNode(head, name, numGuests);
}

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Can't do this as you can see in the link I've posted, the constructro from GuestListNode does not take 3 arguments.

Also, toString() methods should generally not use a println anywhere - thats not their purpose.
It should do something like this:

Code:

---

public String toString() {
  GuestListNode temp = head;
  String s = "";
    while(temp != null){
        s += temp.getName() + " " + temp.getNumGuests() + "\n";
        temp = temp.getNext();
    }
    return s;
}

---

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https://docs.google.com/viewer?a=v&p...MjVmMTcy&hl=en

@OP: please quote properly; I can't quote your last message now because you've added you reply to yet another quote.

About the problem: your assignment also says that a node should be inserted at its correct alphabetical position in the list. Your constructor takes two arguments but you can't set the head of the list to just a single new node.

kind regards,

Jos

Quote:

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Originally Posted by JosAH

@OP: please quote properly; I can't quote your last message now because you've added you reply to yet another quote.

About the problem: your assignment also says that a node should be inserted at its correct alphabetical position in the list. Your constructor takes two arguments but you can't set the head of the list to just a single new node.

kind regards,

Jos

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Well I thought I'd tackle one problem at a time. I thought I first I could have the nodes be printed then work on arranging them properly.

Quote:

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Originally Posted by nomss

Well I thought I'd tackle one problem at a time. I thought I first I could have the nodes be printed then work on arranging them properly.

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You can only print the contents of the Nodes if you have put them in that list; you haven't put them in that list so they are not printed. It's not a catch 22, you have to insert the Nodes in your list.

kind regards,

Jos