Compilare: user.cpp: In function ‘void read()’: user.cpp:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp: In function ‘void init(int, int, int)’: user.cpp:91: warning: comparison between signed and unsigned integer expressions user.cpp:91: warning: comparison between signed and unsigned integer expressions user.cpp:96: warning: comparison between signed and unsigned integer expressions user.cpp:98: warning: comparison between signed and unsigned integer expressions user.cpp: In function ‘void update(int, int, int)’: user.cpp:153: warning: comparison between signed and unsigned integer expressions