[GAP Forum] question from a newbie

[Hannes Riesterer]

Helo,

i have just discovered gap and i have some questions i couldn't figure out.
Is it possible to get all semidirect products of Z^2 by a cyclic group  of 
order n ? Mor pricesly i want to compute the first Cohomology group of all 
such posible extensions, namely the commutator group of them. In the tutorial 
there are only examples of semidirect products of finite groups. I tryed to 
make the same with Z^2 interpreted as the free group generated by ("a","b"), 
but the examples didn't work with that. Thanks for any help.