Compilare: user.cpp: In function ‘bool OK(int)’: user.cpp:28:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < strlen(b); i++) ~~^~~~~~~~~~~ user.cpp: In function ‘int main()’: user.cpp:51:15: warning: unused variable ‘j’ [-Wunused-variable] int q, i, j, balbaiala; ^ user.cpp:51:18: warning: unused variable ‘balbaiala’ [-Wunused-variable] int q, i, j, balbaiala; ^~~~~~~~~