c++ recursive class

Hello everyone!!!

I'd need a little hint on this little question:

I have a xml file I want to navigate and I have a library to process
it. But I want also to manage that file as an object to make clear and
efficient code.
So I coded two class which one is like recursive as like as in this
example:

class B : public xmlnode
{
public:
B(xmlnode* member);

LPCSTR getattribute(....);
void setattribute(....);

xmlnode* Node(LPCSTR nodename, LPCSTR attributenodename, LPCSTR
attributetosearch);

};

class A : public xmldocument
{
public:
A(LPCSTR xmlfilename);

xmlnode* Node(LPCSTR nodename, LPCSTR attributenodename,
LPCSTR attributetosearch);

};

So I can do this:

A* xmlobject = new A(filenamexmlblahblah);
xmlobject->Node(....,....,...)->Node(...,...,...)->GetAttribute(...);

where next nodes are nodes inside a parent node...but I get this link
error:

error LNK2019: unresolved external symbol "public: class B *
__thiscall B::Node(....)" ....

what I could have missed?...
Even I'm just using a function that returns class node itself....

Thanks to everyone!
Ciao
Luigi

It looks like you just forgot to implement the B::Node member function.

By the way, please post your code in [code][/code] bbcode tags.

Yes I just forgot to say I implemented in the CPP file:

Code:

---

xmlnode* xmlnode::Node(LPCSTR nodename,  LPCSTR attributenodename,
LPCSTR
attributetosearch)
{
....

}

---

but still I get that error

That is the definition of xmlnode::Node, not B::Node.

Ah sorry.... I typed wrong... I wanted to say in fact

Code:

---

class B : public xmlnode
{
public:
B(xmlnode* member);

LPCSTR getattribute(....);
void setattribute(....);

B* Node(LPCSTR nodename, LPCSTR attributenodename, LPCSTR
attributetosearch);

};

class A : public xmldocument
{
public:
A(LPCSTR xmlfilename);

B* Node(LPCSTR nodename, LPCSTR attributenodename,
LPCSTR attributetosearch);

};

B* B::Node(LPCSTR nodename,  LPCSTR attributenodename,
LPCSTR
attributetosearch)
{
....

}

---

and I get that error....

Weird. I suggest that you reduce your program to the smallest and simplest program that demonstrates that error, then post the resultant program.

Here the attachment for smallest and simplest demo application which at Button1 click should read the xml file and show in the edit box its value and instead I get this error:

1>prova_tinyxmlDlg.obj : error LNK2019: unresolved external symbol "public: char const * __thiscall documentTinyNode::GetAttribute(char const *)" (?GetAttribute@documentTinyNode@@QAEPBDPBD@Z) referenced in function "public: void __thiscall Cprova_tinyxmlDlg::OnBnClickedButton1(void)" (?OnBnClickedButton1@Cprova_tinyxmlDlg@@QAEXXZ)
1>prova_tinyxmlDlg.obj : error LNK2019: unresolved external symbol "public: class documentTinyNode * __thiscall documentTinyNode::Node(char const *,char const *,char const *)" (?Node@documentTinyNode@@QAEPAV1@PBD00@Z) referenced in function "public: void __thiscall Cprova_tinyxmlDlg::OnBnClickedButton1(void)" (?OnBnClickedButton1@Cprova_tinyxmlDlg@@QAEXXZ)
1>prova_tinyxmlDlg.obj : error LNK2019: unresolved external symbol "public: class documentTinyNode * __thiscall documentTinyXML::Node(char const *,char const *,char const *)" (?Node@documentTinyXML@@QAEPAVdocumentTinyNode@@PBD00@Z) referenced in function "public: void __thiscall Cprova_tinyxmlDlg::OnBnClickedButton1(void)" (?OnBnClickedButton1@Cprova_tinyxmlDlg@@QAEXXZ)
1>prova_tinyxmlDlg.obj : error LNK2019: unresolved external symbol "public: __thiscall documentTinyXML::documentTinyXML(char const *)" (??0documentTinyXML@@QAE@PBD@Z) referenced in function "public: void __thiscall Cprova_tinyxmlDlg::OnBnClickedButton1(void)" (?OnBnClickedButton1@Cprova_tinyxmlDlg@@QAEXXZ)
1>I:\projects\project_tests\prova_tinyxml\Debug\prova_tinyxml.exe : fatal error LNK1120: 4 unresolved externals

Any suggest?...

Hi,
This error: "error LNK2019: unresolved external symbol .. " said
Linker could not find and definition of "documentTinyNode::GetAttribute" (for example)
Take note in your documentTinyNode class has only declaration of GetAttribute method.

and u must implement documentTinyNode::GetAttribute to resolve LNK2019 error

Sorry I forgot something to attach in the package source... here the correct attachment test example... as you can see there are in the .cpp implementations of GetAttribute, SetAttribute and B:Node... but I still get that error...

Thanks
Ciao
Luigi

Quote:

---

Originally Posted by npuleio

Sorry I forgot something to attach in the package source... here the correct attachment test example... as you can see there are in the .cpp implementations of GetAttribute, SetAttribute and B:Node... but I still get that error...

Thanks
Ciao
Luigi

---

:D
Your source code (prova_tinyxmlDlg.cpp) still missing implement documentTinyXML::Node(..)
Please complete implementation and rebuild your project

Ehm... isn't implemented in prova_tinyxmlDlg.cpp almost at begin of the file?....

Ah sorry.... now I understand... I shall implement also documentTinyXML::Node(..) when actually I implemented only documentTinyNode()...

I guess that member documentTinyXML::Node() should be implemented as like:

documentTinyNode* documentTinyXML::Node(LPCSTR nodename, ........ , ....... )
{
documentTinyNode::Node(nodename, ..... , ..... );
}

as an override of the documentTinyNode's function to get a node object... but those two classes aren't of same parent but just different objects... how it should be implemented then?...

Thanks
Ciao
Luigi

Hi,
First of all, You should take a look at http://w3schools.com/xml/xml_tree.asp
"XML documents must contain a root element. This element is "the parent" of all other elements..."

As Xml document tree
the documentTinyXML class should be
class documentTinyXML
{
.....
public:
List<documentTinyNode> GetChildNodes(); // Return a collection of xmlNode
};

There is a good book Programming - Object-Oriented Analysis and Design - C++ to read
and your choose are yours

Merry Christmas !