Global symbol "$r" requires explicit package name at diameter.pl line 5.
Global symbol "$diameter" requires explicit package name at diameter.pl line 6.
Global symbol "$r" requires explicit package name at diameter.pl line 6.
Global symbol "$area" requires explicit package name at diameter.pl line 7.
Global symbol "$r" requires explicit package name at diameter.pl line 7.
Global symbol "$cir" requires explicit package name at diameter.pl line 8.
Global symbol "$diameter" requires explicit package name at diameter.pl line 8.
Global symbol "$r" requires explicit package name at diameter.pl line 9.
Global symbol "$diameter" requires explicit package name at diameter.pl line 9.
Global symbol "$cir" requires explicit package name at diameter.pl line 9.
Global symbol "$area" requires explicit package name at diameter.pl line 9.
Execution of diameter.pl aborted due to compilation errors.