/in/foo.cc: In function 'int main()':
/in/foo.cc:9:32: error: 'N' was not declared in this scope
  cout<<fixed<<setprecision(2)<<N;
                                ^
/in/foo.cc:8:9: warning: unused variable 'fabs' [-Wunused-variable]
  double fabs(n);
         ^~~~