STL code compiling problems in VS 2005

[ankan.banerjee]

I have a piece of STL code which compiled perfectly with VC++ 6.0 and
VS .NET 2003 but I get loads of errors for it in VS 2005.

The code is as follows:

class CTimeKey: public pair<wstring, wstring{};
class CTimeFactors
{
public:
double calendar_factor ;
double calendar_days;
bool pattern_check;
double pattern_factor;
};

class CTimeLine: public map<CTimeKey, CTimeFactors{};

CTimeLine::iter ator l_time_iterator ;
....
if (l_time_iterato r == NULL) {
....
}

The error is for the NULL comparison operation and is as follows:

error C2678: binary '==' : no operator found which takes a left-hand
operand of type 'std::_Tree<_Tr aits>::iterator ' (or there is no
acceptable conversion)
with
[

_Traits=std::_T map_traits<CTim eKey,CTimeFacto rs,std::less<CT imeKey>,std::al locator<std::pa ir<const
CTimeKey,CTimeF actors>>,false>
]
C:\Program Files\Microsoft Visual Studio 8\VC\PlatformSD K
\include\guidde f.h(192): could be 'int operator ==(const GUID &,const
GUID &)'
C:\Program Files\Microsoft Visual Studio 8\VC\include
\xtree(287): or 'bool std::_Tree<_Tra its>::const_ite rator::operator
==(const std::_Tree<_Tra its>::const_ite rator &) const'
with
[

_Traits=std::_T map_traits<CTim eKey,CTimeFacto rs,std::less<CT imeKey>,std::al locator<std::pa ir<const
CTimeKey,CTimeF actors>>,false>
]
while trying to match the argument list
'(std::_Tree<_T raits>::iterato r, int)'
with
[

_Traits=std::_T map_traits<CTim eKey,CTimeFacto rs,std::less<CT imeKey>,std::al locator<std::pa ir<const
CTimeKey,CTimeF actors>>,false>
]
Any ideas how to resolve this?

Thanks and regards,
Ankan

[Carl Daniel [VC++ MVP]]

an************@ gmail.com wrote:

I have a piece of STL code which compiled perfectly with VC++ 6.0 and
VS .NET 2003 but I get loads of errors for it in VS 2005.

Well, first you should probably post in a C++ newsgroup instead of a C#
newsgroup.

>
The code is as follows:

class CTimeKey: public pair<wstring, wstring{};
class CTimeFactors
{
public:
double calendar_factor ;
double calendar_days;
bool pattern_check;
double pattern_factor;
};

class CTimeLine: public map<CTimeKey, CTimeFactors{};

CTimeLine::iter ator l_time_iterator ;
...
if (l_time_iterato r == NULL) {

[snipped more code]

Any ideas how to resolve this?

Iterators are not required to be comparable to null. It might work on some
implementations , but there's no guarantee. Instead, you need to compare the
iterator to another iterator, such as the one returned by end():

if (l_time_iterato r == end())

It's also not a good idea to derive from std::pair or std::map since those
classes weren't designed to work as a base class. As long as you don't ever
call delete through a pointer to the base class, you won't have any
problems, but it's usually recommended to avoid the construct in the first
place.

-cd