/in/foo.cc: In function 'int main()':
/in/foo.cc:6:7: error: 'fioat' does not name a type
 const fioat PI=45
       ^~~~~
/in/foo.cc:5:7: warning: unused variable 'radius' [-Wunused-variable]
 float radius,area;
       ^~~~~~
/in/foo.cc:5:14: warning: unused variable 'area' [-Wunused-variable]
 float radius,area;
              ^~~~