Compilare: main.cpp: In function 'void io::setIn(std::__cxx11::string)': main.cpp:131:56: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] void setIn(string s) { freopen(s.c_str(),"r",stdin); } ^ main.cpp: In function 'void io::setOut(std::__cxx11::string)': main.cpp:132:58: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] void setOut(string s) { freopen(s.c_str(),"w",stdout); } ^