C++ Puzzle! Class without a name

[doublemaster007]

Is it possible to have class without name ?
if so, wat about the constructor and destructors ?
how to create a object of that class ?
how to pass as argument to function ?



..

 

[Noah Roberts]

Can't. Well, you can always pass a void *. But, the function won't have
any idea what to do with it.

class X { public: int f() { return 0; } };

void function(X & x) { x.f(); }

class : public X
{
} foo;


int main()
{
function(foo);
}


Compiles and runs with g++.

 

[James Kanze]

class X { public: int f() { return 0; } };

void function(X & x) { x.f(); }

class : public X
{
} foo;

int main()
{
   function(foo);
}

Compiles and runs with g++.

Which reminds me of a real case of a class without a name which
I use in some cases:

class Callback
{
public:
virtual ~Callback() {}
virtual void visitOne( /* some arguments */ ) = 0 ;
} ;

void visit( Callback& action ) ;

and elsewhere:

void
f()
{
class : public Callback
{
public
virtual void visitOne( /* some arguments */ )
{
// whatever is needed...
}
} action ;
visitor( action ) ;
}

(Most of the time, I'll still give the class a name, however.)

 

[Gennaro Prota]

class X { public: int f() { return 0; } };

void function(X & x) { x.f(); }

class : public X
{
} foo;

int main()
{
function(foo);
}

Compiles and runs with g++.

Which reminds me of a real case of a class without a name which
I use in some cases:

class Callback
{
public:
virtual ~Callback() {}
virtual void visitOne( /* some arguments */ ) = 0 ;
} ;

void visit( Callback& action ) ;

and elsewhere:

void
f()
{
class : public Callback
{
public
virtual void visitOne( /* some arguments */ )
{
// whatever is needed...
}
} action ; [...]
}

That's fine: action has no linkage. (I seriously hope for this
nonsense to go to the Google group someone has created for the
purpose. It's wasting everyone's time with incorrect answers to
incorrect questions. Most of the people involved should be
directed to alt.comp.lang.learn.c-c++)