/in/foo.cc: In function 'int main()':
/in/foo.cc:22:37: warning: 'd' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<fixed<<setprecision(2)<<d/n<<"%"<<endl;
                                     ^~~
/in/foo.cc:21:37: warning: 'f' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<fixed<<setprecision(2)<<f/n<<"%"<<endl;
                                     ^~~
/in/foo.cc:20:37: warning: 'y' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<fixed<<setprecision(2)<<y/n<<"%"<<endl;
                                     ^~~
/in/foo.cc:19:37: warning: 'z' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<fixed<<setprecision(2)<<z/n<<"%"<<endl;
                                     ^~~
/in/foo.cc:7:2: warning: 'i' may be used uninitialized in this function [-Wmaybe-uninitialized]
  for(int i;i<=n;i++)
  ^~~