Compilare: user.cpp: In function 'int check(const char*, int, char)': user.cpp:17: warning: comparison between signed and unsigned integer expressions user.cpp:17: warning: comparison between signed and unsigned integer expressions user.cpp: In function 'll doit(int, const char*)': user.cpp:31: warning: comparison between signed and unsigned integer expressions user.cpp:31: warning: comparison between signed and unsigned integer expressions user.cpp:34: warning: comparison between signed and unsigned integer expressions