1 #pragma clang system_header 2 3 namespace std { 4 class istream { 5 public: 6 bool is_eof(); 7 char get_char(); 8 }; 9 10 istream &operator>>(istream &is, char &c) { 11 if (is.is_eof()) 12 return; 13 c = is.get_char(); 14 } 15 16 extern istream cin; 17 }; 18