foo.cc:5:17: error: 'stdd' is not a namespace-name
 using namespace stdd;
                 ^~~~
foo.cc:5:21: error: expected namespace-name before ';' token
 using namespace stdd;
                     ^
foo.cc: In function 'int main()':
foo.cc:10:5: error: 'cin' was not declared in this scope
     cin>>a>>b>>c;
     ^~~
foo.cc:10:5: note: suggested alternative:
In file included from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:75:0,
                 from foo.cc:4:
/usr/include/c++/7/iostream:60:18: note:   'std::cin'
   extern istream cin;  /// Linked to standard input
                  ^~~
foo.cc:11:5: error: 'cout' was not declared in this scope
     cout<<fixed<<setprecision(c)<<a/b;
     ^~~~
foo.cc:11:5: note: suggested alternative:
In file included from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:75:0,
                 from foo.cc:4:
/usr/include/c++/7/iostream:61:18: note:   'std::cout'
   extern ostream cout;  /// Linked to standard output
                  ^~~~
foo.cc:11:11: error: 'fixed' was not declared in this scope
     cout<<fixed<<setprecision(c)<<a/b;
           ^~~~~
foo.cc:11:11: note: suggested alternative:
In file included from /usr/include/c++/7/ios:42:0,
                 from /usr/include/c++/7/istream:38,
                 from /usr/include/c++/7/sstream:38,
                 from /usr/include/c++/7/complex:45,
                 from /usr/include/c++/7/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:52,
                 from foo.cc:4:
/usr/include/c++/7/bits/ios_base.h:1041:3: note:   'std::fixed'
   fixed(ios_base& __base)
   ^~~~~
foo.cc:11:18: error: 'setprecision' was not declared in this scope
     cout<<fixed<<setprecision(c)<<a/b;
                  ^~~~~~~~~~~~
foo.cc:11:18: note: suggested alternative:
In file included from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:72:0,
                 from foo.cc:4:
/usr/include/c++/7/iomanip:195:3: note:   'std::setprecision'
   setprecision(int __n)
   ^~~~~~~~~~~~
foo.cc:9:12: warning: unused variable 'd' [-Wunused-variable]
     double d;
            ^

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