/in/foo.cc: In function 'int main()':
/in/foo.cc:9:3: warning: 'n' is used uninitialized in this function [-Wuninitialized]
  m=n*n;
  ~^~~~
/in/foo.cc:32:11: warning: 'o' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<o<<" "<<n;
           ^~~