/in/foo.cc: In function 'int main()':
/in/foo.cc:23:33: warning: 'd' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<fixed<<setprecision(2)<<d/n*1.0<<"%"<<endl;
                                ~^~
/in/foo.cc:22:33: warning: 's' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<fixed<<setprecision(2)<<s/n*1.0<<"%"<<endl;
                                ~^~
/in/foo.cc:21:33: warning: 'j' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<fixed<<setprecision(2)<<j/n*1.0<<"%"<<endl;
                                ~^~
/in/foo.cc:20:33: warning: 'w' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<fixed<<setprecision(2)<<w/n*1.0<<"%"<<endl;
                                ~^~
/in/foo.cc:8:2: warning: 'i' may be used uninitialized in this function [-Wmaybe-uninitialized]
  for(int i;i<=n-1;i++)
  ^~~