print undef || "undef is false", "\n";
print 0 || "0 is false", "\n";
print '' || "'' is false", "\n";
print '0' || "'0' is false", "\n";
print '0xxx' || "'0xxx' is false", "\n";
print 'false' || "'0xxx' is false", "\n";
print '1' || "'0xxx' is false", "\n";

##</code><code>##

undef is false
0 is false
'' is false
'0' is false
0xxx
false
1