ListSet.java

public class ListSet<T> implements Set<T>{
  private int find(T e){
    int i = 0; 
    while(elements.hasNext()){
      if(elements.next()==null){
        return -1;
      }else{
        if(e==elements.next(){
          return elements.next()
        }
      }
      temp = elements.next();
      
    }
  }
}