class CharNode {
    private char letter;
    private CharNode next;
    public CharNode(char ch, CharNode link) {

    }
    public void setCharacter(char ch) {
        letter = ch;
    }
    public char getCharacter() {
        return letter;
    }
    public void setNext(CharNode next) {
        this.next = next;
    }
    public CharNode getNext() {
        return next;
    }
}
class CharList {

    private CharNode head;
    // member variable pointing to the head of the linked list

    public CharList(CharList l) {
    // copy constructor (is that the right terminology?)

    }
    public CharList(String s) {
    // constructor from a String

        toString();
    }
    public String toString() {
    // for output purposes -- override Object version

    }
    public void addHead(char ch) {
    // create a new node and add it to the head of the list

    }
    public void addTail(char ch) {
    // create a new node and add it to the tail of the list

    }
    public void reverse() {
    // modify the list so it is reversed

    }
    public void removeChar(char ch) {
    // remove all occurrences of the character from the list

    }
    public int length() {
    // how many nodes in the list

    }
}

class CharNode {
  // As far as I can tell, you are trying to make a doubly linked list
  // So, you'll need your nodes to have a previous pointer as well 
  // as a next
  private char letter;
  private CharNode next;
  private CharNode previous;

  public CharNode(char ch, CharNode next, CharNode previous) {
    setCharacter(ch);
    setNext(next);
    if(previous != null)
      setPrevious(previous);
  }
  public void setCharacter(char ch) {
    letter = ch;
  }
  public char getCharacter() {
    return letter;
  }
  public void setNext(CharNode next) {
    this.next = next;
  }
  public CharNode getNext() {
    return next;
  }
  public void setPrevious(CharNode previous) {
    this.previous = previous;
  }
  public CharNode getPrevious() {
    return previous;
  }
}

public class CharList {

  private CharNode head;
  // member variable pointing to the head of the linked list

  // Because you've got an addTail, you have a doubly linked list
  // so you'll want a pointer to the tail
  private CharNode tail;

  private int nodeCount; // Number of nodes in list

  public CharList(CharList l) {
    // copy constructor (is that the right terminology?)

    // I'll leave you to do this one.  You'll get each 
    // character from l and addChar it to this CharList
  }
  public CharList(String s) {
    char[] ca = s.toCharArray(); // make the string into a
      // char array
    // loop through char array
    for(int i=0;i<ca.length;i++) {
      this.addHead(ca[i]); // adding chars to our linked list
    }
  }

  // for output purposes -- override Object version
  public String toString() {
    CharNode c = tail; // Start at the tail - this is a FILO list
    StringBuffer sb = new StringBuffer();
    for(int i=0;i<length();i++) {
      sb.append(c.getCharacter());
      if(i<(length()-1))
        sb.append("->");
      c=c.getNext();
    }
    return sb.toString();
  }

  // create a new node and add it to the head of the list
  public void addHead(char ch) {    
    CharNode newHead = new CharNode(ch,head,null);
    if(head!=null) {
      head.setNext(newHead);
      newHead.setPrevious(head);
    }
    head=newHead;
    nodeCount++;
    if(length()==1)
      tail=head;
  }
  public void addTail(char ch) {
    // create a new node and add it to the tail of the list
    CharNode newTail = new CharNode(ch,null,tail);
    if(tail!=null) {
      tail.setPrevious(newTail);
      newTail.setNext(tail);
    }
    tail=newTail;
    nodeCount++;
    if(length()==1)
      tail=head;
  }
  public void reverse() {
    // modify the list so it is reversed

  }
  public void removeChar(char ch) {
    // remove all occurrences of the character from the list

  }
  public int length() {
    // how many nodes in the list
    return nodeCount;
  }

  public static void main (String argv[]) {
    CharList cl=new CharList("abcedfghijklmnopqrstuvwxyz");
    cl.addTail('T');
    cl.addHead('H');
    System.out.println(cl.toString());
  }
}