Re: container class for using a struct in std::vector<>

From:
"Victor Bazarov" <v.Abazarov@comAcast.net>
Newsgroups:
microsoft.public.vc.language
Date:
Fri, 12 Jan 2007 15:36:04 -0500
Message-ID:
<eo8rfl$viu$1@news.datemas.de>
PaulH wrote:

On Jan 12, 1:18 pm, "Alex Blekhman" <x...@oohay.moc> wrote:

"PaulH" wrote:

I have a std::vector< ICMP_ECHO_REPLY > container that I'd
like to be
able to do such wonderful STL operations as max_element(),
accumulate(), greater_equal(), etc... So, I decided I
would create a
class to contain that information and overload the
necessary operators.

The idea is that I should be able to do something like
this:

std::vector< ICMP_ECHO_REPLY > container;
ICMP_ECHO_REPLY reply;
//...
container.push_back( reply );
//...
std::vector< ICMP_ECHO_REPLY >::const_iterator itMax =
max_element(
container.begin() container.end() );

Thus far, I've got something like the class below, but I
the error:
error C2678: binary '<' : no operator found which takes a
left-hand
operand of type 'const CEchoReply' (or there is no
acceptable
conversion)

So, first, I'd like to know if there is a better way of
doing this.
Second, what is it I'm doing wrong here?

Thanks,
PaulH

class CEchoReply
{
public:
   ICMP_ECHO_REPLY _reply;
   CEchoReply()
   {
       ZeroMemory( &_reply, sizeof( ICMP_ECHO_REPLY ) );
   };
   CEchoReply( const ICMP_ECHO_REPLY& reply )
   {
       memcpy( &_reply, &reply, sizeof(
ICMP_ECHO_REPLY ) );
   };
   ~CEchoReply()
   {
   };
   operator ICMP_ECHO_REPLY() const { return _reply; };
   bool operator < ( const ICMP_ECHO_REPLY& lhs )
   {
       return lhs.RoundTripTime < _reply.RoundTripTime;
   };

- Hide quoted text -
- Show quoted text -
};In addition to Victor's reply, you could inherit CEchoReply

from ICMP_ECHO_REPLY struct. Then you won't need `operator
ICMP_ECHO_REPLY' and `_reply' member anymore. Also, avoid
names starting from underscore ('_') in your programs. Such
names are reserved by C++ Standard for the implementation.


I always love a method that uses less code! Thanks!


If you inherit from ICMP_ECHO_REPLY, then the consturctor does
not need to call ZeroMemory, you can just initialise the base
class:

    CEchoReply() : ICMP_ECHO_REPLY() {} // notice the parens

and you didn't (and don't) need the copy c-tor, the compiler-
generated one should do nicely.

V
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