/in/foo.cc: In function 'int main()':
/in/foo.cc:4:5: error: 'db' was not declared in this scope
    4 |     db v,g,m,n;
      |     ^~
/in/foo.cc:5:15: error: 'v' was not declared in this scope
    5 |     std::cin>>v>>g>>m>>n;
      |               ^
/in/foo.cc:5:18: error: 'g' was not declared in this scope
    5 |     std::cin>>v>>g>>m>>n;
      |                  ^
/in/foo.cc:5:21: error: 'm' was not declared in this scope; did you mean 'tm'?
    5 |     std::cin>>v>>g>>m>>n;
      |                     ^
      |                     tm
/in/foo.cc:5:24: error: 'n' was not declared in this scope; did you mean 'yn'?
    5 |     std::cin>>v>>g>>m>>n;
      |                        ^
      |                        yn