/in/foo.cc: In function 'void read()':
/in/foo.cc:6:2: error: 'cin' was not declared in this scope
cin>>n;
^~~
/in/foo.cc:6:2: note: suggested alternative:
In file included from /in/foo.cc:2:0:
/usr/include/c++/6/iostream:60:18: note: 'std::cin'
extern istream cin; /// Linked to standard input
^~~
/in/foo.cc: In function 'void put()':
/in/foo.cc:18:2: error: 'cout' was not declared in this scope
cout<<t;
^~~~
/in/foo.cc:18:2: note: suggested alternative:
In file included from /in/foo.cc:2:0:
/usr/include/c++/6/iostream:61:18: note: 'std::cout'
extern ostream cout; /// Linked to standard output
^~~~