/in/foo.cc: In function 'int main()':
/in/foo.cc:17:7: error: 'cout' was not declared in this scope
       cout<<left<<setw(4);
       ^~~~
/in/foo.cc:17:13: error: 'left' was not declared in this scope
       cout<<left<<setw(4);
             ^~~~
/in/foo.cc:17:25: error: 'setw' was not declared in this scope
       cout<<left<<setw(4);
                         ^
/in/foo.cc:18:35: error: 'endl' was not declared in this scope
       cout<<hen<<setw(4)<<rabbit<<endl;
                                   ^~~~
/in/foo.cc:6:13: warning: unused variable 'hen' [-Wunused-variable]
  int rabbit,hen;//数量
             ^~~