Compilare: user.cpp: In function ‘void open_file()’: user.cpp:10:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("evaluare.in", "r", stdin); ^ user.cpp:11:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("evaluare.out", "w", stdout); ^ user.cpp: In function ‘void read()’: user.cpp:15:30: warning: ignoring return value of ‘char* fgets(char*, int, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fgets(exp, 100005, stdin); ^