Here is the code we wrote today. First the OurList interface:

public interface OurList< T> {

    public void add(T s);  //adds s to end

    public int size();    //returns size of list

    public boolean contains(T s);  //returns whether s is in the list
    
    public void clear();  //empties list

}

public class OurLinkedList< T> implements OurList< T> {

    private Node head;  //points to head of list

    private class Node {
        T value;
        Node next;

        public Node(T value, Node next) {
            this.value = value;
            this.next = next;
        }
    }

    public void addFront(T newItem) {
        head = new Node(newItem, head);
    }

    public boolean contains(T s) {
        Node curr = head;
        while(curr != null) {
            if(curr.value.equals(s))
                return true;
            curr = curr.next;
        }
        return false;
    }

    public int size() {
	    Node curr = head;
	    int count = 0;
	    while(curr != null) {
            count++;
            curr = curr.next;
	    }
	    return count;
    }

    public void clear() {
        head = null;
    }

    public void add(T toAdd) {       //add to end of the list
	    Node curr = head;
        Node newNode = new Node(toAdd, null);
        if(curr == null) {  //special case: adding to empty list
            head = newNode;
            return;
        }
	    while(curr.next != null)
		    curr = curr.next;
	    curr.next= newNode;
    }

}