At a guess I'd say you can't do that. have you tried it? There are probably some scope issues about it.
Could do something like this:
Very ... basic example. You can use member functions within classes. Goto's are generally a bad idea. Only real use I've had for them would be for getting out of deep nesting in loops and such. Don't use them often at all.
thing( int new_num )
std::cout<< "Starting Constructor ... \n";
initialise( new_num );
std::cout<< "Ending Constructor ... \n";
void initialise ( int new_num )
std::cout<< "Starting Initialiser ... \n";
num = new_num;
std::cout<< "Ending Initialiser ... \n";
int main( void )
thing whatever( 42 );