Compilare: user.cpp: In function ‘int ret(std::pair<int, int>)’: user.cpp:35:17: warning: unused variable ‘from’ [-Wunused-variable] int from ,to, up; ^ user.cpp:35:23: warning: unused variable ‘to’ [-Wunused-variable] int from ,to, up; ^ user.cpp:35:27: warning: unused variable ‘up’ [-Wunused-variable] int from ,to, up; ^