/in/foo.cc: In function 'int main()':
/in/foo.cc:6:2: error: 'folat' was not declared in this scope
  folat sum=0;
  ^~~~~
/in/foo.cc:12:3: error: 'sum' was not declared in this scope
   sum+=float(fenzi)/fenmu;
   ^~~
/in/foo.cc:17:16: error: 'sum' was not declared in this scope
  printf("%.2f",sum);
                ^~~