Hello!
The file versuch.lhs (attachment) consists of a function gc2. If you try gc2 25 15, hugs produces a run time error.
gc2 ist defined as:
> gc2::Int->Int->Int
> gc2 a1 a2 = gc2 a2 (mod a1 a2)
> gc2 a2 0 = a2
CU
Fabian Meier