Compilare: user.cpp: In function ‘int perm(int)’: user.cpp:38:12: warning: suggest explicit braces to avoid ambiguous ‘else’ [-Wparentheses] if (valid(k)) ^ user.cpp:42:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^ user.cpp: In function ‘int valid2()’: user.cpp:30:1: warning: control reaches end of non-void function [-Wreturn-type] } ^