Re: NULL

From:

"Jim Langston" <tazmaster@rocketmail.com>

Newsgroups:

comp.lang.c++

Date:

Sat, 23 Jun 2007 09:19:02 -0700

Message-ID:

<vKbfi.13$A7.5@newsfe04.lga>

"Mohitz" <coolmohitz@gmail.com> wrote in message
news:1182423813.025225.16600@i38g2000prf.googlegroups.com...

How do you write a function in C++ which returns a class object in
some cases and in others, returns something like a NULL pointer so
that i can know in the callee function that the object doesnt exist??

ClassName A()
{
  ClassName a;
  if (condition)
       return a;
  else

Returning a pointer (as others have commented on) is a valid method. The
method I use for this, however, is to throw, since I want to return a
reference.

CPlayer& FindPlayer( const std::string Name )
{
    for ( map_player::iterator i = World.ConnectedPlayers.begin(); i !=
World.ConnectedPlayers.end(); ++i)
    {
        if ( (*i).second.Character.Name == Name )
            return (*i).second;
    }

    throw 0;

}

//////////////////

   try
   {
       CPlayer& TargetPlayer = FindPlayer( Name );
       PlayerMoveTo( TargetPlayer, ThisPlayer.Character.Map,
ThisPlayer.Character.Pos );
       SendMessageToPlayer( Socket, MSG_SERVER_MESSAGE, Name + "
summoned." );
   }
   catch ( int )
   {
       SendMessageToPlayer( Socket, MSG_SERVER_MESSAGE, Name + " not
found." );
   }