遍历二叉树

//前序遍历
void former_traverse(BTree *root)
{
    Stack s;
    BTree *p = root;

    while (p != NULL | !s.empty())
    {
        while (p != NULL)
        {
            cout << p->data << endl;
            s.push(p);
            p = p->left;
        }

        if (!s.empty())
        {
            p = p.top();
            p.pop();
            p = p->right();
        }
    }
}

//中序遍历
void middle_traverse(BTree *root)
{
    Stack s;
    BTree *p = root;

    while (p != NULL | !s.empty())
    {
        while (p != NULL)
        {
            s.push(p);
            p = p->left;
        }

        if (!s.empty())
        {
            p = s.pop();
            cout << p->data << endl;
            s.pop();
            p = p->right();
        }
    }
}

//后序遍历
void last_traverse(BTree *root)
{
    Stack s;
    BTree *p = root;
    BTNode *temp = NULL;

    while (p != NULL | !s.empty())
    {
        while (p != NULL)
        {
            temp = (BTNode *)malloc(sizeof(BTNode));
            temp->btnode = p;
            temp->isFirst = true;
            s.push(temp);
            p = p->left;
        }

        if (!s.empty())
        {
            temp = s.top();
            s.pop();
            if (temp->isFirst == true)
            {
                temp->isFirst = false;
                s.push(temp);
                p = temp->btnode->right;
            }
            else
            {
                cout << temp->btnode->datae;
                p = NULL;
            }
        }
    }
}