二叉排序树中序遍历

二叉排序树的中序遍历是按照左子树、根节点、右子树的顺序遍历整棵树。具体实现可以使用递归或者非递归方式。以下是两种实现方式：

1. 递归方式

public void inOrder(TreeNode treeNode) {
    if (treeNode == null) {
        return;
    }
    inOrder(treeNode.leftChild);
    System.out.print(treeNode.data + " ");
    inOrder(treeNode.rightChild);
}

2. 非递归方式

public void inOrder(TreeNode treeNode) {
    Stack<TreeNode> stack = new Stack<>();
    TreeNode current = treeNode;
    while (current != null || !stack.isEmpty()) {
        while (current != null) {
            stack.push(current);
            current = current.leftChild;
        }
        current = stack.pop();
        System.out.print(current.data + " ");
        current = current.rightChild;
    }
}