Compilare: user.cpp: In function ‘void read()’: user.cpp:52: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp:53: warning: ignoring return value of ‘int fscanf(FILE*, const char*, ...)’, declared with attribute warn_unused_result user.cpp: In function ‘void write()’: user.cpp:59: warning: comparison between signed and unsigned integer expressions