/in/foo.cc: In function 'int main()':
/in/foo.cc:5:9: error: 'double3' was not declared in this scope; did you mean 'double'?
    5 |         double3 x;
      |         ^~~~~~~
      |         double
/in/foo.cc:6:14: error: 'x' was not declared in this scope
    6 |         cin>>x;
      |              ^