/in/foo.cc: In function 'int main()':
/in/foo.cc:7:9: error: 's' was not declared in this scope
    7 |         s=r*r*3.1415926*h;
      |         ^
/in/foo.cc:8:17: error: 'v' was not declared in this scope
    8 |     n=int(20000/v)
      |                 ^
/in/foo.cc:14:9: error: 'else' without a previous 'if'
   14 |         else
      |         ^~~~