Compilare: user.cpp: In function ‘int cmp(const void*, const void*)’: user.cpp:7:9: warning: variable ‘x’ set but not used [-Wunused-but-set-variable] int x,y; ^ user.cpp:7:11: warning: variable ‘y’ set but not used [-Wunused-but-set-variable] int x,y; ^ user.cpp:10:1: warning: no return statement in function returning non-void [-Wreturn-type] } ^