how to derive a CArray method
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I have a member variable declared as: CArray m_dotArray; When I am using it, I use CArray::Add to add new dots to it. But I don't want to add duplicate dot, so I derived CMyArray in the following manner:
template <class TYPE, class ARG_TYPE>
class CMyArray : public CArray < TYPE, ARG_TYPE >
{
public:
int AddThis(ARG_TYPE newElement);
};template < class TYPE, class ARG_TYPE >
int CMyArray < TYPE, ARG_TYPE > ::AddThis(ARG_TYPE newElement)
{
ARG_TYPE existingElement;
for ( int i = 0; i < GetSize(); i ++ )
{
existingElement = GetAt(i);
if ( existiingElement == newElement )
return -1;
}
Add(newElement);
return 0;
}but when compiling the following error is reported: error LNK2001: unresolved external symbol "public: int __thiscall CMyArray < class CPoint, class CPoint > ::AddThis(class CPoint)" ...... What did I miss? :confused: TIA!!
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I have a member variable declared as: CArray m_dotArray; When I am using it, I use CArray::Add to add new dots to it. But I don't want to add duplicate dot, so I derived CMyArray in the following manner:
template <class TYPE, class ARG_TYPE>
class CMyArray : public CArray < TYPE, ARG_TYPE >
{
public:
int AddThis(ARG_TYPE newElement);
};template < class TYPE, class ARG_TYPE >
int CMyArray < TYPE, ARG_TYPE > ::AddThis(ARG_TYPE newElement)
{
ARG_TYPE existingElement;
for ( int i = 0; i < GetSize(); i ++ )
{
existingElement = GetAt(i);
if ( existiingElement == newElement )
return -1;
}
Add(newElement);
return 0;
}but when compiling the following error is reported: error LNK2001: unresolved external symbol "public: int __thiscall CMyArray < class CPoint, class CPoint > ::AddThis(class CPoint)" ...... What did I miss? :confused: TIA!!
Is the function implementation in the header file (or a #included inline file)? If it is in a .cpp file, then the compiler won't find it when instantiating the template, and so the function will be missing at link-time. Dave
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Is the function implementation in the header file (or a #included inline file)? If it is in a .cpp file, then the compiler won't find it when instantiating the template, and so the function will be missing at link-time. Dave
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Is this code visible to your project ? Is it part of your project ? Have you ever tried std::vector ? Unlike CArray, it's powerful, flexible and does not suck. Christian No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002
C# will attract all comers, where VB is for IT Journalists and managers - Michael P Butler 05-12-2002
Again, you can screw up a C/C++ program just as easily as a VB program. OK, maybe not as easily, but it's certainly doable. - Jamie Nordmeyer - 15-Nov-2002 -
ah Yes. I implemented it in cpp file. After I delete the cpp and move the function definition to the .h file, everything is okay. Thank you so much! :laugh::laugh: I am so happy.
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std::vector - code bloat... CAtlArray :) Tim Smith I'm going to patent thought. I have yet to see any prior art.
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std::vector - code bloat... CAtlArray :) Tim Smith I'm going to patent thought. I have yet to see any prior art.
lol - you just don't give up, do you ? I've never used CAtlArray, is it part of WTL ? How complete is it ? That is, does it offer algorithms etc, or is it merely another container of the sort I could write in an afternoon ? Christian No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002
C# will attract all comers, where VB is for IT Journalists and managers - Michael P Butler 05-12-2002
Again, you can screw up a C/C++ program just as easily as a VB program. OK, maybe not as easily, but it's certainly doable. - Jamie Nordmeyer - 15-Nov-2002 -
Thank god someone answered your QUESTION. The style police should take a rest. :) Tim Smith I'm going to patent thought. I have yet to see any prior art.
Like you, I have noticed that there are a lot of posters that preach certain methods for doing specfic tasks. While, I think it is OK to provide alternative appoaches to solve a problem...I also think that you should try to answer the question, as posed. Gary Kirkham A working Program is one that has only unobserved bugs
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Thank god someone answered your QUESTION. The style police should take a rest. :) Tim Smith I'm going to patent thought. I have yet to see any prior art.
Be fair - I NEVER recommend STL unless I can also answer the question, or the question has been answered. I may not have got it right, but I had a guess. And the MFC container classes are still a pile of fetid refuse. Christian No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002
C# will attract all comers, where VB is for IT Journalists and managers - Michael P Butler 05-12-2002
Again, you can screw up a C/C++ program just as easily as a VB program. OK, maybe not as easily, but it's certainly doable. - Jamie Nordmeyer - 15-Nov-2002 -
lol - you just don't give up, do you ? I've never used CAtlArray, is it part of WTL ? How complete is it ? That is, does it offer algorithms etc, or is it merely another container of the sort I could write in an afternoon ? Christian No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002
C# will attract all comers, where VB is for IT Journalists and managers - Michael P Butler 05-12-2002
Again, you can screw up a C/C++ program just as easily as a VB program. OK, maybe not as easily, but it's certainly doable. - Jamie Nordmeyer - 15-Nov-2002Christian Graus wrote: or is it merely another container of the sort I could write in an afternoon ? For 10 points, explain how a "mere container" is a bad thing. -c
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Be fair - I NEVER recommend STL unless I can also answer the question, or the question has been answered. I may not have got it right, but I had a guess. And the MFC container classes are still a pile of fetid refuse. Christian No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002
C# will attract all comers, where VB is for IT Journalists and managers - Michael P Butler 05-12-2002
Again, you can screw up a C/C++ program just as easily as a VB program. OK, maybe not as easily, but it's certainly doable. - Jamie Nordmeyer - 15-Nov-2002Christian Graus wrote: And the MFC container classes are still a pile of fetid refuse. Is there an article you can direct me to that will show what you're talking about? If not, I see it as a great opportunity to once again demonstrate your overnight article-writing abilities ;P:-). Regards, Alvaro
Well done is better than well said. -- Benjamin Franklin (I actually prefer medium-well.)
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Christian Graus wrote: And the MFC container classes are still a pile of fetid refuse. Is there an article you can direct me to that will show what you're talking about? If not, I see it as a great opportunity to once again demonstrate your overnight article-writing abilities ;P:-). Regards, Alvaro
Well done is better than well said. -- Benjamin Franklin (I actually prefer medium-well.)
Yes, that was a major reason I wrote my article on std::vector, to point out all the things that it does that CArray will not. CArray is a perfectly good array class ( they are not hard to write ). But how do you copy the contents of a CArray into a CList or CMap ? STL containers provide a common iterator interface. How do you sort a CArray, or shuffle it, or any other common algorithm ? The stl comes with all sorts of algorithms, and the facility to easily write more. Christian No offense, but I don't really want to encourage the creation of another VB developer. - Larry Antram 22 Oct 2002
C# will attract all comers, where VB is for IT Journalists and managers - Michael P Butler 05-12-2002
Again, you can screw up a C/C++ program just as easily as a VB program. OK, maybe not as easily, but it's certainly doable. - Jamie Nordmeyer - 15-Nov-2002