template overloading operator c++ 6 to vs2005

  • Thread starter Thread starter AlanJSmith
  • Start date Start date
A

AlanJSmith

I am converting some C++ projects from 6 to vs2005

I turned off precompiled headers and common lanuage runtime
support.

template<int nSize> class DBString
{
public:

// Indicates status of string, eg. length, NULL
long nIndicator;

// array of characters of appropriate length holds actual data
unsigned char strValue[((nSize/4)%4==0)? nSize : (nSize/4)*4];

// copy assignment different size oporator
template<int nInSize> operator =(const DBString<nInSize>& strNewValue)
{
_strncpy_s((char*)strValue,nSize,(char*)strNewValue.strValue,nInSize);
}

// copy assignment (same size)
DBString<nSize> DBString<nSize>::operator =(const DBString<nSize>&
strNewValue)
{
_strncpy_s((char*)strValue,nSize,(char*)strNewValue.strValue,nSize);
nIndicator = strNewValue.nIndicator;
}

};


The syntax of the decaration causes me this error when
trying to compile.

\DBString.cpp(12) : error C4430: missing type specifier - int assumed. Note:
C++ does not support default-int
1> .\DBString.cpp(24) : see reference to class template instantiation
'DBString<nSize>' being compiled

I had added DBString<nSize>
DBString<nSize>:: to the copy assignment same size oporator as this was
giving same error and this
seems to work, if i try the same thing with copy assignment different
sizes i get error C3856: 'DBString<nSize>::=': class is not a class
template and adding any type between template<int nInSize> and
operator = without the DBString<nSize>:: gives me a c++ optimizer had
to close send error report to microsoft error.

obviously i have tried lots of variations on the syntax but i am still
flummoxed, there is the chance that what i am trying to do is not allowed in
VS2005 but i am not sure.
 
AlanJSmith said:
I am converting some C++ projects from 6 to vs2005

I turned off precompiled headers and common lanuage runtime
support.
[code snipped]

The syntax of the decaration causes me this error when
trying to compile.
Click to expand...

VC6 was letting you getting away with some really loose code there. The
canonical form for copy-assignment operators is this:

// copy assignment different size oporator
template<int nInSize>
DBString& operator =(const DBString<nInSize>& strNewValue)
{
_strncpy_s((char*)strValue,nSize,(char*)strNewValue.strValue,nInSize);
return *this;
}

// copy assignment (same size)
DBString<nSize>& operator =(const DBString<nSize>& strNewValue)
{
_strncpy_s((char*)strValue,nSize,(char*)strNewValue.strValue,nSize);
nIndicator = strNewValue.nIndicator;
return *this;
}

which compiles just fine with VC8.

-cd
 
:
AlanJSmith said:
I am converting some C++ projects from 6 to vs2005

I turned off precompiled headers and common lanuage runtime
support.
[code snipped]

The syntax of the decaration causes me this error when
trying to compile.
Click to expand...

VC6 was letting you getting away with some really loose code there. The
canonical form for copy-assignment operators is this:

// copy assignment different size oporator
template<int nInSize>
DBString& operator =(const DBString<nInSize>& strNewValue)
{

_strncpy_s((char*)strValue,nSize,(char*)strNewValue.strValue,nInSize);
return *this;
}

// copy assignment (same size)
DBString<nSize>& operator =(const DBString<nSize>& strNewValue)
{

_strncpy_s((char*)strValue,nSize,(char*)strNewValue.strValue,nSize);
nIndicator = strNewValue.nIndicator;
return *this;
}

which compiles just fine with VC8.

-cd
Click to expand...

Thank you Carl this is exactly what i was after the correct canonical
syntax. I am far from an expert in C++ but have been tasked with upgrading
the code written by someone else 11 years ago to a supported IDE.

If I could ask a favour, what book would you recomend as a reference ie: you
favourite C++ reference.

Regards,
Alan Smith
 
AlanJSmith said:
:
Thank you Carl this is exactly what i was after the correct canonical
syntax. I am far from an expert in C++ but have been tasked with
upgrading the code written by someone else 11 years ago to a
supported IDE.
If I could ask a favour, what book would you recomend as a reference
ie: you favourite C++ reference.
Click to expand...

First, go to www.accu.org and look through their book reviews. They have
100's of them on nearly every C and C++ book ever written.

To bring you up to speed, many people recommend:
"Accelerated C++" by Andrew Koenig and Barbara Moo.
"Thinking in C++" by Bruce Eckel. This book is available online for free:
http://www.mindview.net/Books/TICPP/ThinkingInCPP2e.html

For a more detailed language reference, the standard is "The C++ Programming
Language, 3rd ed." by Bjarne Stroustrup.

For the C++ standard library, the standard reference is "The C++ Standard
Library", by Nicolai Jusittus.

There are several books by Scott Meyers (Effective C++, More Effective C++,
Effective STL, More Effective STL, etc). These are all excellent and useful
books. Of all of these, "Effective C++" is a must-have for someone coming
up to speed on the subtleties of the language.

There are several books by Herb Sutter (Exceptional C++, More Exceptional
C++, etc). These are also excellent books.

Yeah, it's a lot of books - but then, C++ is a complex language used to do
complex things, so it takes a lot of books!

-cd
 
Carl Daniel said:
First, go to www.accu.org and look through their book reviews. They have
100's of them on nearly every C and C++ book ever written.

To bring you up to speed, many people recommend:
"Accelerated C++" by Andrew Koenig and Barbara Moo.
"Thinking in C++" by Bruce Eckel. This book is available online for free:
http://www.mindview.net/Books/TICPP/ThinkingInCPP2e.html

For a more detailed language reference, the standard is "The C++
Programming Language, 3rd ed." by Bjarne Stroustrup.

For the C++ standard library, the standard reference is "The C++ Standard
Library", by Nicolai Jusittus.

There are several books by Scott Meyers (Effective C++, More Effective
C++, Effective STL, More Effective STL, etc). These are all excellent and
useful books. Of all of these, "Effective C++" is a must-have for someone
coming up to speed on the subtleties of the language.

There are several books by Herb Sutter (Exceptional C++, More Exceptional
C++, etc). These are also excellent books.

Yeah, it's a lot of books - but then, C++ is a complex language used to do
complex things, so it takes a lot of books!

-cd
Click to expand...
Thank you Carl,

I have ordered, "The C++ Programming Language, 3rd ed." by Bjarne Stroustrup
and "The C++ Standard Library", by Nicolai Jusittus.

Thank you again for all your help.

Alan Smith
 
Back
Top