foo.cc: In function 'int main()':
foo.cc:8:9: error: 'cin' was not declared in this scope; did you mean 'std::cin'?
    8 |         cin>>a>>b>>c>>d;
      |         ^~~
      |         std::cin
In file included from stdc++.h:75:
/nix/store/np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0/include/c++/12.2.0/iostream:60:18: note: 'std::cin' declared here
   60 |   extern istream cin;           /// Linked to standard input
      |                  ^~~
foo.cc:9:9: error: 'cout' was not declared in this scope; did you mean 'std::cout'?
    9 |         cout<<a<<' '<<b<<' '<<fixed<<setprecision(6)<<c<<' '<<d;
      |         ^~~~
      |         std::cout
/nix/store/np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0/include/c++/12.2.0/iostream:61:18: note: 'std::cout' declared here
   61 |   extern ostream cout;          /// Linked to standard output
      |                  ^~~~
foo.cc:9:31: error: 'fixed' was not declared in this scope; did you mean 'std::fixed'?
    9 |         cout<<a<<' '<<b<<' '<<fixed<<setprecision(6)<<c<<' '<<d;
      |                               ^~~~~
      |                               std::fixed
In file included from /nix/store/np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0/include/c++/12.2.0/ios:42,
                 from /nix/store/np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0/include/c++/12.2.0/istream:38,
                 from /nix/store/np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0/include/c++/12.2.0/sstream:38,
                 from /nix/store/np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0/include/c++/12.2.0/complex:45,
                 from /nix/store/np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0/include/c++/12.2.0/ccomplex:39,
                 from stdc++.h:54:
/nix/store/np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0/include/c++/12.2.0/bits/ios_base.h:1080:3: note: 'std::fixed' declared here
 1080 |   fixed(ios_base& __base)
      |   ^~~~~
foo.cc:9:38: error: 'setprecision' was not declared in this scope; did you mean 'std::setprecision'?
    9 |         cout<<a<<' '<<b<<' '<<fixed<<setprecision(6)<<c<<' '<<d;
      |                                      ^~~~~~~~~~~~
      |                                      std::setprecision
In file included from stdc++.h:72:
/nix/store/np14qqgvvnyna3vv640hmhi21flymiia-gcc-12.2.0/include/c++/12.2.0/iomanip:195:3: note: 'std::setprecision' declared here
  195 |   setprecision(int __n)
      |   ^~~~~~~~~~~~

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