// file IntList.java
// Recursive functions over linked list of ints.
//


// Linked list of int. No header, empty lists not permitted.

public class IntList {
    private int value;     
    private IntList next;
  
    public IntList(int v, IntList n) {          // Constructor
        value = v;
        next = n;
      }

    public int getValue() { return value; }       // Getters
    public IntList getNext() { return next; }
    public void setValue(int v) { value = v; }    // Setters
    public void setNext(IntList n) { next = n; }

// Find the last node of a linked list.
    public IntList findLast() {
       if (getNext() == null) return this;
       else return getNext().findLast();
     }

// Add a new node with value v at the end of l;

    public void addEnd(int v) {
        findLast().setNext(new IntList(v,null));
      }

// Add up the values in a list, recurring down the owner
    public int sumList() {
       if (getNext() == null) return getValue();
       else return getValue() + getNext().sumList();
      }

// Convert list of int to string

// Recursive method for constructing the end of the string, after the
// initial open bracket.

   public String toString1() {
       if (getNext() == null)
          return getValue() + "]";
       else return getValue() + ", " + getNext().toString1();
     }

// Top level rountine that starts with the "[" and then calls toString1 to
// do the rest.

   public String toString() {
        return "[" + toString1();
     }

// Recursive method for finding the sum of a list, using recursion down
// an argument. Note that this is a static method, associated with the class
// not with an object owner.

   static public int sumListArg(IntList l) {
        if (l==null) return 0;
        else return l.getValue() + sumListArg(l.getNext());
       }

   static public void main(String[] args) {
       IntList l = new IntList(2,null);
       l.addEnd(3);
       l.addEnd(5);
       l.addEnd(7);
       System.out.println(l.toString());
       System.out.println("Sum = " + l.sumList());
    } // end main
} // end RecursiveIntList