Question

• Adapt the original LinkList class to use the generic Gnode class

Code for LinkList below

class LinkList {
    Node llist;

    LinkList( int sz ) {
   if ( sz <= 0 ) {
       llist = null;
   }
   else {
       // start with list of size 1
       llist = new Node( "0", null ); 
       Node current = llist; // temp node for loop
       // add further nodes
       for ( int i=1; i<sz; ++i ) {
      // create node and attach it to the list
      Node node2Add = new Node( Integer.toString(i), null );
      current.setNext(node2Add);   // add first node
      current=node2Add;
       }
   }
    }
    
    /**
     * Print all the elements of the list assuming that they are Strings
     */
    public void print() {
   /* Print the list */
   Node current = llist; // point to the first node
   while (current != null) {
       System.out.print((String)current.getElement() + " ");  
       current = current.getNext(); // move to the next
   }
   System.out.println();  
    }

    public void deleteFirst() {
   if ( llist != null ) {
       llist = llist.getNext();
   }
    }

    public void deleteLast() {
   if ( llist == null ) return; // no node
   Node prev = llist;
   Node current = prev.getNext(); 
   if ( current == null ) { // only 1 node
       llist = null;
       return;
   }
   while ( current.getNext() != null ) { // more than 1 node
       prev = current;
       current = current.getNext();
   }
   prev.setNext( null );
   return;
    }

    // create and display a linked list
    public static void main(String [] args){
   /* Create the list */
   LinkList llist = new LinkList( 5 );
   /* Print the list */
   llist.print();
   /* delete first and print */
   llist.deleteFirst();
   llist.print();
   /* delete last and print 5 times */
   for ( int i=0; i< 5; ++i ) {
       llist.deleteLast();
       llist.print();
   }
    }
}

Code for GNODE below

public class GNode<E> {
  // Instance variables:
  private E element;
  private GNode<E> next;
  /** Creates a node with null references to its element and next node. */
  public GNode() {
    this(null, null);
  }
  /** Creates a node with the given element and next node. */
  public GNode(E e, GNode<E> n) {
    element = e;
    next = n;
  }
  // Accessor methods:
  public E getElement() {
    return element; 
  }
  public GNode<E> getNext() { 
    return next;
  }
  // Modifier methods:
  public void setElement(E newElem) { 
    element = newElem; 
  }
  public void setNext(GNode<E> newNext) {
    next = newNext; 
  }
}

Answer 1

CODE

class LinkList {
   GNode<String> llist;

    LinkList( int sz ) {
   if ( sz <= 0 ) {
       llist = null;
   }
   else {
       // start with list of size 1
       llist = new GNode<>( "0", null );
       GNode<String> current = llist; // temp node for loop
       // add further nodes
       for ( int i=1; i<sz; ++i ) {
      // create node and attach it to the list
           GNode<String> node2Add = new GNode<>( Integer.toString(i), null );
      current.setNext(node2Add);   // add first node
      current=node2Add;
       }
   }
    }
  
    /**
     * Print all the elements of the list assuming that they are Strings
     */
    public void print() {
   /* Print the list */
       GNode<String> current = llist; // point to the first node
   while (current != null) {
       System.out.print((String)current.getElement() + " ");
       current = current.getNext(); // move to the next
   }
   System.out.println();
    }

    public void deleteFirst() {
   if ( llist != null ) {
       llist = llist.getNext();
   }
    }

    public void deleteLast() {
   if ( llist == null ) return; // no node
   GNode<String> prev = llist;
   GNode<String> current = prev.getNext();
   if ( current == null ) { // only 1 node
       llist = null;
       return;
   }
   while ( current.getNext() != null ) { // more than 1 node
       prev = current;
       current = current.getNext();
   }
   prev.setNext( null );
   return;
    }

    // create and display a linked list
    public static void main(String [] args){
   /* Create the list */
   LinkList llist = new LinkList( 5 );
   /* Print the list */
   llist.print();
   /* delete first and print */
   llist.deleteFirst();
   llist.print();
   /* delete last and print 5 times */
   for ( int i=0; i< 5; ++i ) {
       llist.deleteLast();
       llist.print();
   }
    }
}