ples help me with expression tree java
<p>i have expreesion tree and i want to inoreder travsel in tostring method it should remove unnessary parenthesese ihave done preorder 
plese help me 
this is my code</p>

<pre><code>public class ExpTree {
    private int kind;
    private Object value;
    private ExpTree lChild, rChild;
    public static final int numNode =0, idNode= 1, opNode=2;

  //add extra node kind for colon, comma, and definition node
     public ExpTree (int knd, Object val, ExpTree l, ExpTree r)
     {
         kind =knd;
         value =val;
         lChild= l;
         rChild = r;

     }

    public void preOreder()
    {
         System.out.println(value);
         if (lChild!= null)
             lChild.preOreder();
        if(rChild != null)
            rChild.preOreder();

    }
    public int evalEX()
    {int result =1;
       int a =0;
        int b=1;

     return result;
    }
    public String toString() {


    }
}
</code></pre>
