C / C++ / MFC

LinkedList Template - LNK2019

24-Sep-04 6:06

How's it going with this exercise?

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

Re: function problem

Anonymous24-Sep-04 6:57

Anonymous

24-Sep-04 6:57

Good..I got it takeing care of....thanks for checking up on me! I have so much trouble with this class. I"m strungling to pass =\

~Jason

Milby00715-Sep-04 4:06

Milby007

15-Sep-04 4:06

hi!

i've just finished writing a linked list template class, which compiles fine, but when i try to use it in another file (main.cpp) in my console test app' i get LNK2019 errors for every method of the class being used. i've copied the class & output below, so if anyone has any ideas i would REALLY appreciate some help because i'm completely stuck!! thanks!!

#ifndef _LINKEDLIST_H_
#define _LINKEDLIST_H_

#pragma message (" -+- COMPILING " __FILE__)

// declare classes...

template <class type> class ListElement;
template <class type> class LinkedList;

/*
************************
linkedlist class
************************
*/

template <class type> class LinkedList
{
public:

//
// constructor/destructor
//

LinkedList<type>();
~LinkedList<type>();

//
// public methods
//

bool InsertNext(ListElement<type>* pElement, const type* pData);
bool RemoveNext(ListElement<type>* pElement, type** ppData);

ListElement<type>* GetHead();
ListElement<type>* GetTail();

int GetSize();

bool IsHead(const ListElement<type>& element);
bool IsTail(const ListElement<type>& element);
bool IsEmpty();

ListElement<type>* GetElementByIndex(int index);

LinkedList<type>* Clone();
LinkedList<type>* Copy();

void FreeData();

private:

//
// private methods
//

void SetHead(ListElement<type>* pHead);
void SetTail(ListElement<type>* pTail);
void SetSize(int size);

//
// private member data
//

int m_size;
ListElement<type>* m_pHead;
ListElement<type>* m_pTail;

};

/*
*************************
listelement class
*************************
*/

template <class type> class ListElement
{
public:

//
// constructor/destructor
//

ListElement();
~ListElement();

//
// public methods
//

type* GetData();
void SetData(type* pData);

void FreeData();

ListElement<type>* GetNext();
void SetNext(ListElement<type>* pNext);

type* CloneData();

private:

//
// private member data
//

type* m_pData;
ListElement<type>* m_pNext;

};

#endif // _LINKEDLIST_H_

#pragma message (" -+- COMPILING " __FILE__)

#include <stdlib.h>
#include "linkedlist.h"

/*
************************
linkedlist class
************************
*/

template <class type>
LinkedList<type>::LinkedList() : m_size(0), m_pHead(NULL), m_pTail(NULL)
{
// do nothing
}

template <class type>
LinkedList<type>::~LinkedList()
{
if (m_pHead != NULL)
delete m_pHead;
}

template <class type>
bool LinkedList<type>::InsertNext(ListElement<type>* pElement, const type* pData)
{
ListElement<type>* pNewElement = new ListElement<type>;

if (pNewElement == NULL)
return false;

pNewElement->SetData(const_cast<type*> (pData));

if (pElement == NULL) // insertion @ head of list...
{
if (this->GetSize() == 0)
this->SetTail(pNewElement);

pNewElement->SetNext(this->GetHead());
this->SetHead(pNewElement);
}
else // insertion somewhere other than @ the head...
{
if (pElement->GetNext() == NULL)
this->SetTail(pNewElement);

pNewElement->SetNext(pElement->GetNext());
pElement->SetNext(pNewElement);
}

this->SetSize(this->GetSize() + 1);

return true;
}

template <class type>
bool LinkedList<type>::RemoveNext(ListElement<type>* pElement, type** ppData)
{
ListElement<type>* pOldElement;

if (this->GetSize() == 0)
return false;

// if null then handle removal from head of list...
if (pElement == NULL)
{
*ppData = this->GetHead()->GetData();
pOldElement = this->GetHead();
this->SetHead(this->GetHead()->GetNext());

if (this->GetSize() == 1)
{
this->SetTail(NULL);
}
}
else
{
if (pElement->GetNext() == NULL)
return false;

*ppData = pElement->GetNext()->GetData();
pOldElement = pElement->GetNext();
pElement->SetNext(pElement->GetNext()->GetNext());

if (pElement->GetNext() == NULL)
{
this->SetTail(pElement);
}
}

delete pOldElement;

this->SetSize(this->GetSize() - 1);

return true;
}

template <class type>
ListElement<type>* LinkedList<type>::GetHead()
{
return m_pHead;
}

template <class type>
ListElement<type>* LinkedList<type>::GetTail()
{
return m_pTail;
}

template <class type>
int LinkedList<type>::GetSize()
{
return m_size;
}

template <class type>
bool LinkedList<type>::IsHead(const ListElement<type>& element)
{
return this->GetHead() == element ? true : false;
}

template <class type>
bool LinkedList<type>::IsTail(const ListElement<type>& element)
{
return this->GetTail() == element ? true : false;
}

template <class type>
bool LinkedList<type>::IsEmpty()
{
return this->GetSize() == 0 ? true : false;
}

template <class type>
ListElement<type>* LinkedList<type>::GetElementByIndex(int index)
{
int i;
ListElement<type>* pTmp = NULL;

if (this->GetSize() == 0 || index >= this->GetSize())
return pTmp;

pTmp = this->GetHead(); // element zero

for (i = 1; i <= index; i++)
{
pTmp = pTmp->GetNext();
}

return pTmp;
}

template <class type>
LinkedList<type>* LinkedList<type>::Clone()
{
LinkedList<type>* pNewList = NULL;
ListElement<type>* pSrcElement = NULL;

if (this->GetSize() == 0)
return pNewList;

pNewList = new LinkedList<type>;
pSrcElement = this->GetHead();

pNewList->InsertNext(NULL, pSrcElement->CloneData());

while (pSrcElement->GetNext() != NULL)
{
pSrcElement = pSrcElement->GetNext();

pNewList->InsertNext(pNewList->GetTail(), pSrcElement->CloneData());
}

return pNewList;
}

template <class type>
LinkedList<type>* LinkedList<type>::Copy()
{
LinkedList<type>* pNewList = NULL;
ListElement<type>* pSrcElement = NULL;

if (this->GetSize() == 0)
return pNewList;

pNewList = this;
pSrcElement = this->GetHead();

pNewList->InsertNext(NULL, pSrcElement->CloneData());

while (pSrcElement->GetNext() != NULL)
{
pSrcElement = pSrcElement->GetNext();

pNewList->InsertNext(pNewList->GetTail(), pSrcElement->GetData());
}

return pNewList;
}

template <class type>
void LinkedList<type>::FreeData() // only call when data is allocated on the heap
{
ListElement<type>* pElement = NULL;

if (this->GetSize() == 0)
return;

pElement = this->GetHead();
pElement->FreeData();

while (pElement->GetNext() != NULL)
{
pElement = pElement->GetNext();
pElement->FreeData();
}
}

template <class type>
void LinkedList<type>::SetHead(ListElement<type>* pHead)
{
m_pHead = pHead;
}

template <class type>
void LinkedList<type>::SetTail(ListElement<type>* pTail)
{
m_pTail = pTail;
}

template <class type>
void LinkedList<type>::SetSize(int size)
{
m_size = size;
}

/*
*************************
listelement class
*************************
*/

template <class type>
ListElement<type>::ListElement<type>() : m_pData(NULL), m_pNext(NULL)
{
// do nothing
}

template <class type>
ListElement<type>::~ListElement<type>()
{
if (m_pNext != NULL)
delete m_pNext;
}

template <class type>
type* ListElement<type>::GetData()
{
return m_pData;
}

template <class type>
void ListElement<type>::SetData(type* pData)
{
m_pData = pData;
}

template <class type>
void ListElement<type>::FreeData()
{
if (m_pData != NULL)
delete m_pData;
}

template <class type>
ListElement<type>* ListElement<type>::GetNext()
{
return m_pNext;
}

template <class type>
void ListElement<type>::SetNext(ListElement<type>* pNext)
{
m_pNext = pNext;
}

template <class type>
type* ListElement<type>::CloneData()
{
type* pNewData = new type;

*pNewData = *m_pData;

return pNewData;
}

Linking...
main.obj : error LNK2019: unresolved external symbol "public: __thiscall Stack<int,100>::~Stack<int,100>(void)" (??1?$Stack@H$0GE@@@QAE@XZ) referenced in function "void __cdecl stackfunc(void)" (?stackfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: __thiscall Stack<double,30>::~Stack<double,30>(void)" (??1?$Stack@N$0BO@@@QAE@XZ) referenced in function "void __cdecl stackfunc(void)" (?stackfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: void __thiscall Stack<int,100>::push(int const &)" (?push@?$Stack@H$0GE@@@QAEXABH@Z) referenced in function "void __cdecl stackfunc(void)" (?stackfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: void __thiscall Stack<double,30>::push(double const &)" (?push@?$Stack@N$0BO@@@QAEXABN@Z) referenced in function "void __cdecl stackfunc(void)" (?stackfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: bool __thiscall Stack<int,100>::isEmpty(void)const " (?isEmpty@?$Stack@H$0GE@@@QBE_NXZ) referenced in function "void __cdecl stackfunc(void)" (?stackfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: __thiscall Stack<double,30>::Stack<double,30>(void)" (??0?$Stack@N$0BO@@@QAE@XZ) referenced in function "void __cdecl stackfunc(void)" (?stackfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: __thiscall Stack<int,100>::Stack<int,100>(void)" (??0?$Stack@H$0GE@@@QAE@XZ) referenced in function "void __cdecl stackfunc(void)" (?stackfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: class LinkedList<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > > * __thiscall LinkedList<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >::Clone(void)" (?Clone@?$LinkedList@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@@QAEPAV1@XZ) referenced in function "void __cdecl listfunc(void)" (?listfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: class ListElement<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > > * __thiscall LinkedList<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >::GetElementByIndex(int)" (?GetElementByIndex@?$LinkedList@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@@QAEPAV?$ListElement@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@@H@Z) referenced in function "void __cdecl listfunc(void)" (?listfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: class ListElement<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > > * __thiscall ListElement<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >::GetNext(void)" (?GetNext@?$ListElement@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@@QAEPAV1@XZ) referenced in function "void __cdecl listfunc(void)" (?listfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: class ListElement<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > > * __thiscall LinkedList<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >::GetHead(void)" (?GetHead@?$LinkedList@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@@QAEPAV?$ListElement@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@@XZ) referenced in function "void __cdecl listfunc(void)" (?listfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: int __thiscall LinkedList<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >::GetSize(void)" (?GetSize@?$LinkedList@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@@QAEHXZ) referenced in function "void __cdecl listfunc(void)" (?listfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: class ListElement<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > > * __thiscall LinkedList<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >::GetTail(void)" (?GetTail@?$LinkedList@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@@QAEPAV?$ListElement@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@@XZ) referenced in function "void __cdecl listfunc(void)" (?listfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: bool __thiscall LinkedList<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >::InsertNext(class ListElement<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > > *,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const *)" (?InsertNext@?$LinkedList@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@@QAE_NPAV?$ListElement@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@@PBV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) referenced in function "void __cdecl listfunc(void)" (?listfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > * __thiscall ListElement<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >::GetData(void)" (?GetData@?$ListElement@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@@QAEPAV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@XZ) referenced in function "void __cdecl listfunc(void)" (?listfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: void __thiscall ListElement<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >::SetData(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > *)" (?SetData@?$ListElement@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@@QAEXPAV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) referenced in function "void __cdecl listfunc(void)" (?listfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: __thiscall ListElement<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >::ListElement<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >(void)" (??0?$ListElement@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@@QAE@XZ) referenced in function "void __cdecl listfunc(void)" (?listfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: __thiscall LinkedList<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >::LinkedList<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >(void)" (??0?$LinkedList@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@@QAE@XZ) referenced in function "void __cdecl listfunc(void)" (?listfunc@@YAXXZ)

main.obj : error LNK2019: unresolved external symbol "public: __thiscall LinkedList<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >::~LinkedList<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >(void)" (??1?$LinkedList@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@@QAE@XZ) referenced in function "public: void * __thiscall LinkedList<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >::`scalar deleting destructor'(unsigned int)" (??_G?$LinkedList@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@@QAEPAXI@Z)
Debug/list_test.exe : fatal error LNK1120: 19 unresolved externals

list_test - 20 error(s), 2 warning(s)

---------------------- Done ----------------------

Build: 0 succeeded, 1 failed, 0 skipped

David Crow15-Sep-04 4:44

15-Sep-04 4:44

You might want to use <pre> tags in the future so that code is readable. Does main.cpp include the file linkedlist.h?

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

Milby00715-Sep-04 5:08

Milby007

15-Sep-04 5:08

here's a bit of main.cpp:

#include <string>
#include <iostream>

using namespace std;

#include "linkedlist.h"

void listfunc()
{
ListElement<string>* pStrElmt = NULL;
LinkedList<string>* pStrList = new LinkedList<string>;

string sData1("NUMERO UNO!");
string sData2("NUMERO DOS!");
string sData3("NUMERO TRES!");
string sData4("NUMERO QUATRO!");
string sData5("NUMERO CINQO!");

// element 1

pStrElmt = new ListElement<string>;

pStrElmt->SetData(&sData1);

pStrList->InsertNext(NULL, pStrElmt->GetData());

// element 2

pStrElmt = new ListElement<string>;

pStrElmt->SetData(&sData2);

pStrList->InsertNext(pStrList->GetTail(), pStrElmt->GetData());

// etc...

as you can see i've #include'd where needed, & it's compiled fine, but the linker doesn't like it.

jmkhael15-Sep-04 5:04

jmkhael

15-Sep-04 5:04

Seems like you didnt add the file to your project via Project->Add to project->File

Papa

while (TRUE)
Papa.WillLove ( Bebe ) ;

Milby00715-Sep-04 5:20

Milby007

15-Sep-04 5:20

i'm pretty sure i did.

i'm using vs.net 2003, & added all files to the project by doing:

'project->add new item' (or it's equivalent)

there's a beginners template tutorial (part 1) on this site submitted by a chap called stefan spenz which i copied into my project in the usual way i.e. class definition into header & class implementation into source file (.cpp), then i tried to build the project with the class being used in main.cpp (with #include "stack.h" for new class where needed) and i had the same problem.

i'm obviously missing something about templates!?

Re: What does *.hpp mean?

Bob Stanneveld15-Sep-04 6:31

Bob Stanneveld

15-Sep-04 6:31

Milby007 wrote:
there's a beginners template tutorial (part 1) on this site submitted by a chap called stefan spenz which i copied into my project in the usual way i.e. class definition into header & class implementation into source file (.cpp), then i tried to build the project with the class being used in main.cpp (with #include "stack.h" for new class where needed) and i had the same problem.

There is your problem. You should include the template implementation in the header file. Read this[^] faq about C++ templates and you should do fine...

Multiply it by infinity and take it beyond eternity and you'll still have no idea about what I'm talking about.

What does *.hpp mean?

mcgahanfl15-Sep-04 2:41

mcgahanfl

15-Sep-04 2:41

Example:
#include <tuple.hpp>

What does the hpp mean? Is it just for the human eye? Is it any different to the compiler than a .h file?

thanks

David Crow15-Sep-04 2:50

Re: What does *.hpp mean?

15-Sep-04 2:50

It's the name of a header file for a corresponding .cpp file. With C, you have .c and .h files. With C++, you have .cpp and .hpp files. In the past 15 years, I've never used a .hpp file.

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

markkuk15-Sep-04 3:16

markkuk

15-Sep-04 3:16

It's just for the human eye, the compiler doesn't care.

Re: What does *.hpp mean?

Henry miller15-Sep-04 3:45

Henry miller

15-Sep-04 3:45

The compiler does not care. SOME (but not all) editors switch to C++ mode when the see *.hpp.

Thank you Dave, Mark and Henry.

mcgahanfl15-Sep-04 4:34

mcgahanfl

15-Sep-04 4:34

All good insight.

Bizarre Close dialog action

brianwelsch15-Sep-04 2:22

15-Sep-04 2:22

I've got an About CDialog that has 2 buttons on it (OK, Release Notes). When I click the 'X' to close the dialog it acts as though I clicked on the Release Notes button. Confused | :confused:

I can close the dialog by clicking OK, any ideas on getting it to close on 'X'?

BW
The Biggest Loser

"Farm Donkey makes us laugh.
Farm Donkey hauls some ass."
-The Stoves

Cedric Moonen15-Sep-04 2:35

Cedric Moonen

15-Sep-04 2:35

Make sure the ID of the 'Release Notes' buttons is not IDCANCEL.

brianwelsch15-Sep-04 4:18

15-Sep-04 4:18

Ah, good thought, but no it's ID_RELEASE.

BW
The Biggest Loser

"Farm Donkey makes us laugh.
Farm Donkey hauls some ass."
-The Stoves

David Crow15-Sep-04 4:58

15-Sep-04 4:58

brianwelsch wrote:
...it acts as though I clicked on the Release Notes button.

So when the "X" is clicked, the handler function for the "Release Notes" button is getting called. Yes?

What is the value of ID_RELEASE?

What does the About dialog's message map look like?

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

brianwelsch15-Sep-04 5:42

15-Sep-04 5:42

DavidCrow wrote:
So when the "X" is clicked, the handler function for the "Release Notes" button is getting called. Yes?
Yes

What is the value of ID_RELEASE?
2

What does the About dialog's message map look like?

BEGIN_MESSAGE_MAP(CAboutDlg, CDialog)<br />
	//{{AFX_MSG_MAP(CAboutDlg)<br />
	ON_BN_CLICKED(ID_RELEASE, OnRelease)<br />
	//}}AFX_MSG_MAP<br />
END_MESSAGE_MAP()

BW
The Biggest Loser

"Farm Donkey makes us laugh.
Farm Donkey hauls some ass."
-The Stoves

David Crow15-Sep-04 5:48

15-Sep-04 5:48

brianwelsch wrote:
What is the value of ID_RELEASE?
2

Change it to 102 and it'll work! Wink | ;)

;)

Here's the reason: IDCANCEL has a value of 2.

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

brianwelsch15-Sep-04 7:33

15-Sep-04 7:33

I changed it, but had the same issue. I ended out renaming the ID, deleting the old ID and creating a new button with the old ID name. It got a new random ID value, and all's good.

Thanks for your help, David.
Smile | :)

BW
The Biggest Loser

"Farm Donkey makes us laugh.
Farm Donkey hauls some ass."
-The Stoves

David Crow15-Sep-04 7:45

15-Sep-04 7:45

brianwelsch wrote:
It got a new random ID value...

Actually, there not random at all. They are controlled by the _APS_NEXT_CONTROL_VALUE macro at the bottom of the project's resource.h file.

"When I was born I was so surprised that I didn't talk for a year and a half." - Gracie Allen

Disable F8 at startup

sirtimid15-Sep-04 2:08

sirtimid

15-Sep-04 2:08

Does anyone know how to disable the safe mode of windows?

Thanks in advance

Last open documents

bouli15-Sep-04 1:41

bouli

15-Sep-04 1:41

Hi gurus,

I'd like to know how to
1) save the list of all open documents in an MDI before closing the application and the last active document
1) reload the documents when the MDI application starts.

Thanks Smile | :)

Best regards.

There is no spoon.

Re: Last open documents

David Crow15-Sep-04 2:51