这是我复制数据结构书的代码，想弄头文件，但编译出现很多错误。请高手帮帮

template <typename Comparable>
class BinarySearchTree
{
  public:
    BinarySearchTree( );
    BinarySearchTree( const BinarySearchTree & rhs );
    ~BinarySearchTree( );

    const Comparable & findMin( ) const;
    const Comparable & findMax( ) const;
    bool contains( const Comparable & x ) const;
    bool isEmpty( ) const;
    void printTree( ) const;

    void makeEmpty( );
    void insert( const Comparable & x );
    void remove( const Comparable & x );

    const BinarySearchTree & operator=( const BinarySearchTree & rhs );

  private:
    struct BinaryNode
    {
       Comparable element;
       BinaryNode *left;
       BinaryNode *right;

       BinaryNode( const Comparable & theElement, BinaryNode *lt, BinaryNode *rt )
         : element( theElement ), left( lt ), right( rt ) { }
    };

    BinaryNode *root;

    void insert( const Comparable & x, BinaryNode * & t ) const;
    void remove( const Comparable & x, BinaryNode * & t ) const;
    BinaryNode * findMin( BinaryNode *t ) const;
    BinaryNode * findMax( BinaryNode *t ) const;
    bool contains( const Comparable & x, BinaryNode *t ) const;
    void makeEmpty( BinaryNode * & t );
    void printTree( BinaryNode *t ) const;
    BinaryNode * clone( BinaryNode *t ) const;
};



    bool contains( const Comparable & x ) const   //公有调用私有 图4-17
    {
        return contains( x, root );
    }
        
   
    void insert( const Comparable & x )
    {
        insert( x, root );
    }
   
   
    void remove( const Comparable & x )
    {
        remove( x, root );
    }



    bool contains( const Comparable & x, BinaryNode *t ) const  //contains操作
    {
        if( t == NULL )
            return false;
        else if( x < t->element )
            return contains( x, t->left );
        else if( t->element < x )
            return contains( x, t->right );
        else
            return true;  

           BinaryNode * findMin( BinaryNode *t ) const  //findmin
    {
        if( t == NULL )
            return NULL;
        if( t->left == NULL )
            return t;
        return findMin( t->left );
    }

            BinaryNode * findMax( BinaryNode *t ) const   //findmax
    {
        if( t != NULL )
            while( t->right != NULL )
                t = t->right;
        return t;
    }

            void insert( const Comparable & x, BinaryNode * & t )     //insert  操作
    {
        if( t == NULL )
            t = new BinaryNode( x, NULL, NULL );
        else if( x < t->element )
            insert( x, t->left );
        else if( t->element < x )
            insert( x, t->right );
        else
            ;  // Duplicate; do nothing

        void remove( const Comparable & x, BinaryNode * & t )     //remove   操作
    {
        if( t == NULL )
            return;   // Item not found; do nothing
        if( x < t->element )
            remove( x, t->left );
        else if( t->element < x )
            remove( x, t->right );
        else if( t->left != NULL && t->right != NULL ) // Two children
        {
            t->element = findMin( t->right )->element;
            remove( t->element, t->right );
        }
        else
        {
            BinaryNode *oldNode = t;
            t = ( t->left != NULL ) ? t->left : t->right;
            delete oldNode;
        }
    }

template <typename Comparable>bool BinarySearchTree::contains( const Comparable & x ) const
{
     return contains( x, root );
}
BinaryNode在private中定义，外部怎么还可以访问