password.cpp:6:11: error: 'string' was not declared in this scope; did you mean 'std::string'?
6 | int query(string str);
| ^~~~~~
| std::string
In file included from /usr/include/c++/10/iosfwd:39,
from /usr/include/c++/10/ios:38,
from /usr/include/c++/10/istream:38,
from /usr/include/c++/10/sstream:38,
from /usr/include/c++/10/complex:45,
from /usr/include/c++/10/ccomplex:39,
from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
from password.cpp:4:
/usr/include/c++/10/bits/stringfwd.h:79:33: note: 'std::string' declared here
79 | typedef basic_string<char> string;
| ^~~~~~
password.cpp:8:1: error: 'string' does not name a type; did you mean 'stdin'?
8 | string guess(int n, int s)
| ^~~~~~
| stdin