C++ 抽象类-语法帮助

我在抽象类方面有点问题。我有很多课。在StackAsLinkedList.h类中，我有一个指向对象的指针链接列表，如图所示

LinkedList<Object*> list;

下面是stackaslinklist.cpp文件，它无法识别列表

#include "StackAsLinkedList.h"
#include "NullObject.h"
#include "List_Element.h"
#include "Stack.h"
#include "Linked_List.h"
#include "Container.h"


//void StackAsLinkedList::Accept (Visitor& visitor) const
//{
// ListElement<Object*> const* ptr;

//for (ptr = list.Head ();
//ptr != 0 && !visitor.IsDone (); ptr = ptr->Next ())
// {
//visitor.Visit (*ptr->Datum ());
// }
//}




StackAsLinkedList::StackAsLinkedList () : list ()
{

}

void StackAsLinkedList::Purge ()
{
if (IsOwner ())
{
ListElement<Object*> const* ptr;

for (ptr = list.Head(); ptr != 0; ptr = ptr->Next ())
    delete ptr->Datum ();
}

list.Purge ();
count = 0;
}

StackAsLinkedList::~StackAsLinkedList ()
{ 
    Purge (); 

}



void StackAsLinkedList::Push (Object& object)
{
list.Prepend (&object);
++count;
}

Object& StackAsLinkedList::Pop ()
{
if (count == 0)
throw domain_error ("stack is empty");
Object& const result = *list.First ();
list.Extract (&result);
--count;
return result;
}

Object& StackAsLinkedList::Top () const
{
if (count == 0)
throw domain_error ("stack is empty");
return *list.First ();
}



StackAsLinkedList::Iter::Iter (
StackAsLinkedList const& _stack) :
stack (_stack)
{ Reset (); }

bool StackAsLinkedList::Iter::IsDone () const
{ return position == 0; }

Object& StackAsLinkedList::Iter::operator * () const
{
if (position != 0)
return *position->Datum ();
else
return NullObject::Instance ();
}

void StackAsLinkedList::Iter::operator ++ ()
{
if (position != 0)
position = position->Next ();
}

void StackAsLinkedList::Iter::Reset ()
{ position = stack.list.Head (); }

StackAsLinkedList::StackAsLinkedList () : list ()

我遇到的一些错误是：注意：第一个错误将我带到我的原始问题：

 LinkedList<Object*> list;

 error C2143: syntax error : missing ';' before '<'
 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
 error C2238: unexpected token(s) preceding ';'
 error C2433: 'StackAsLinkedList::Iter::position' : 'virtual' not permitted on data declarations
 error C2614: 'StackAsLinkedList' : illegal member initialization: 'list' is not a base or member
 error C2065: 'list' : undeclared identifier
 error C2228: left of '.Head' must have class/struct/union
 error C2065: 'list' : undeclared identifier
 error C2228: left of '.Purge' must have class/struct/union

LinkedList列表；
错误C2143:语法错误：缺少“；”在“之前，听起来LinkedList类对StackAsLinkedList类不可见。在“StackAsLinkedList.h”的顶部包括“LinkedList.h”

#include "StackAsLinkedList.h"
#include "NullObject.h"
#include "List_Element.h"
#include "Stack.h"
#include "Linked_List.h"
#include "Container.h"


//void StackAsLinkedList::Accept (Visitor& visitor) const
//{
// ListElement<Object*> const* ptr;

//for (ptr = list.Head ();
//ptr != 0 && !visitor.IsDone (); ptr = ptr->Next ())
// {
//visitor.Visit (*ptr->Datum ());
// }
//}




StackAsLinkedList::StackAsLinkedList () : list ()
{

}

void StackAsLinkedList::Purge ()
{
if (IsOwner ())
{
ListElement<Object*> const* ptr;

for (ptr = list.Head(); ptr != 0; ptr = ptr->Next ())
    delete ptr->Datum ();
}

list.Purge ();
count = 0;
}

StackAsLinkedList::~StackAsLinkedList ()
{ 
    Purge (); 

}



void StackAsLinkedList::Push (Object& object)
{
list.Prepend (&object);
++count;
}

Object& StackAsLinkedList::Pop ()
{
if (count == 0)
throw domain_error ("stack is empty");
Object& const result = *list.First ();
list.Extract (&result);
--count;
return result;
}

Object& StackAsLinkedList::Top () const
{
if (count == 0)
throw domain_error ("stack is empty");
return *list.First ();
}



StackAsLinkedList::Iter::Iter (
StackAsLinkedList const& _stack) :
stack (_stack)
{ Reset (); }

bool StackAsLinkedList::Iter::IsDone () const
{ return position == 0; }

Object& StackAsLinkedList::Iter::operator * () const
{
if (position != 0)
return *position->Datum ();
else
return NullObject::Instance ();
}

void StackAsLinkedList::Iter::operator ++ ()
{
if (position != 0)
position = position->Next ();
}

void StackAsLinkedList::Iter::Reset ()
{ position = stack.list.Head (); }

StackAsLinkedList::StackAsLinkedList () : list ()

 LinkedList<Object*> list;

 error C2143: syntax error : missing ';' before '<'
 error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
 error C2238: unexpected token(s) preceding ';'
 error C2433: 'StackAsLinkedList::Iter::position' : 'virtual' not permitted on data declarations
 error C2614: 'StackAsLinkedList' : illegal member initialization: 'list' is not a base or member
 error C2065: 'list' : undeclared identifier
 error C2228: left of '.Head' must have class/struct/union
 error C2065: 'list' : undeclared identifier
 error C2228: left of '.Purge' must have class/struct/union