二叉树的遍历

     //先序遍历
    public void preOrder(BinaryNode root){
        if(root!=null){
            System.out.print(root.data+"\t");
            preOrder(root.left);
            preOrder(root.right);
        }
    }
    //后序遍历
    public void postOrder(BinaryNode root){
        if(root!=null){
            postOrder(root.left);
            postOrder(root.right);
            System.out.print(root.data+"\t");
        }
    }

    //中序遍历
    public void inOrder(BinaryNode root){
        if(root!=null){
            inOrder(root.left);
            System.out.print(root.data+"\t");
            inOrder(root.right);
        }
    }

    /**
     * 非迭代先序遍历
     * @param root
     */
    public void preOrderNoIte(BinaryNode root){
        BinaryNode c;
        Stack<BinaryNode> stack = new Stack<BinaryNode>();
        stack.push(root);
        while(!stack.empty()){
            c = stack.pop();
            System.out.print(c.data+"\t");
            if(c.right!=null) {
                stack.push(c.right);
            }
            if(c.left!=null) {
                stack.push(c.left);
            }
        }
    }




    /**
     * 非迭代中序遍历
     * @param root
     */
    public void inOrderNoIte(BinaryNode root){
        Stack<BinaryNode> stack = new Stack<BinaryNode>();
        BinaryNode c = root;
        while(c!=null || !stack.empty()){
            while(c!=null) {
                stack.push(c);
                c = c.left;
            }
            c= stack.pop();
            System.out.print(c.data+"\t");
            c = c.right;

        }
    }

    /**
     * 非迭代后序遍历
     * @param root
     */
    public void postOrderNoIte(BinaryNode root){
        BinaryNode c,rNode = null;
        Stack<BinaryNode> stack = new Stack<BinaryNode>();

         c = root;
        while(c!=null || !stack.empty()){

            while(c !=null ){
                stack.push(c);
                c = c.left;
            }
            c = stack.pop();

            while(c!=null && (c.getRight()==null || c.getRight()== rNode)){
                System.out.print(c.data+"\t");
                rNode = c;
                if(stack.empty()){
                    return;
                }
                c = stack.pop();
            }
            stack.push(c);
            c = c.getRight();

        }
    }