/in/foo.cc: In function 'int main()':
/in/foo.cc:9:39: warning: format '%lf' expects argument of type 'double', but argument 2 has type 'int' [-Wformat=]
    9 |         int a,b;cin>>a>>b;printf("%.9lf",a/b);
      |                                   ~~~~^  ~~~
      |                                       |   |
      |                                       |   int
      |                                       double
      |                                   %.9d