Before I add serialize to Element (Both .h and .cpp), My sketcher compile well.
After I add serialize in ch17 (until to page 881 in ivor 2005 book), when I compile I got this message

------ Build started: Project:
Sketcher, Configuration: Debug Win32 ------
Linking...
Elements.obj : error LNK2019: unresolved external symbol "protected: __thiscall CLine::CLine(void)" ([email protected]@[email protected]) referenced in function "public: static class CObject * __stdcall CLine::CreateObject(void)" ([email protected]@@[email protected]@XZ)
Elements.obj : error LNK2019: unresolved external symbol "protected: __thiscall CRectangle::CRectangle(void)" ([email protected]@[email protected]) referenced in function "public: static class CObject * __stdcall CRectangle::CreateObject(void)" ([email protected]@@[email protected]@XZ)
Elements.obj : error LNK2019: unresolved external symbol "protected: __thiscall CCircle::CCircle(void)" ([email protected]@[email protected]) referenced in function "public: static class CObject * __stdcall CCircle::CreateObject(void)" ([email protected]@@[email protected]@XZ)
Elements.obj : error LNK2019: unresolved external symbol "protected: __thiscall CCurve::CCurve(void)" ([email protected]@[email protected]) referenced in function "public: static class CObject * __stdcall CCurve::CreateObject(void)" ([email protected]@@[email protected]@XZ)
Elements.obj : error LNK2019: unresolved external symbol "protected: __thiscall CEllipse::CEllipse(void)" ([email protected]@[email protected]) referenced in function "public: static class CObject * __stdcall CEllipse::CreateObject(void)" ([email protected]@@[email protected]@XZ)
C:\Documents and Settings\Administrator\My Documents\Visual Studio 2008\Projects\Sketcher\Debug\Sketcher.exe : fatal error LNK1120: 5 unresolved externals
Build log was saved at "file://c:\Documents and Settings\Administrator\My Documents\Visual Studio 2008\Projects\Sketcher\Sketcher\Debug\BuildLog.htm "
Sketcher - 6 error(s), 0 warning(s)
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

I am try to compare my sketcher with ivor's code (download from wrox website).But it's not differrent. I am not sure I am do something wrong. Anyone can help me please...
Thank for advance
Chang

Now I can solve that problem. Thank you for your read.

I'm having the same issue when I try to compile after adding the serilization code. Does anyone have an answer to this problem.

I know it's too late to answer your question but I am sure someone will run into the same problem one day.
My solution to the problem was as simple as adding a constructor for each of the elements in the Elements class.
Add the following lines in the Elements.cpp file:

CLine::CLine()
{
}
CRectangle::CRectangle()
{
}
CCircle::CCircle()
{
}
CCurve::CCurve()
{
}
CEllipse::CEllipse()
{
}

For some reason when I added the constructor for the Text class I got an error that the function already has a body so just forget about the Text constructor definition.
I hope this helps
Regards,
Marwa