Compilare: user.cpp: In function ‘int main()’: user.cpp:87: warning: comparison between signed and unsigned integer expressions user.cpp:81: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result user.cpp:82: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result