Example Linked List

package example.linklist;
 
class Link {
    public int key;
 
    public double data;
 
    public Link next;
 
    public Link(int id, double dd) {
	key = id;
	data = dd;
    }
 
    public void displayLink() {
	System.out.print("{" + key + ", " + data + "} ");
    }
}
 
public class AnotherLinkList {
    private Link first;
 
    public AnotherLinkList() {
	first = null;
    }
 
    public void insertFirst(int id, double dd) {
	Link newLink = new Link(id, dd);
	newLink.next = first;
	first = newLink;
    }
 
    public Link find(int key) {
	Link current = first;
	while (current.key != key) {
	    if (current.next == null)
		return null; // didn't find it
	    else
		// not end of list,
		current = current.next; // go to next link
	}
	return current; // found it
    }
 
    // delete link with given key
    public Link delete(int key) {
	Link current = first;
	Link previous = first;
	while (current.key != key) {
	    if (current.next == null)
		return null; // didn't find it
	    else {
		previous = current; // go to next link
		current = current.next;
	    }
	} // found it
	if (current == first) // if first link,
	    first = first.next; // change first
	else
	    // otherwise,
	    previous.next = current.next; // bypass it
	return current;
    }
 
    public void displayList() {
	System.out.print("List (first to last): ");
	Link current = first;
	while (current != null) {
	    current.displayLink();
	    current = current.next;
	}
	System.out.println("");
    }
 
    public static void main(String[] args) {
	AnotherLinkList theList = new AnotherLinkList();
 
	theList.insertFirst(12, 2.59);
	theList.insertFirst(24, 4.69);
	theList.insertFirst(36, 6.79);
	theList.insertFirst(48, 8.89);
 
	theList.displayList();
 
	Link f = theList.find(44);
	if (f != null)
	    System.out.println("Found link with key " + f.key);
	else
	    System.out.println("Can't find link");
 
	Link d = theList.delete(66);
	if (d != null)
	    System.out.println("Deleted link with key " + d.key);
	else
	    System.out.println("Can't delete link");
 
	theList.displayList();
    }
}