/in/foo.cc: In function 'void hanoi(int, int, int, int)':
/in/foo.cc:46:24: warning: 'sum3' may be used uninitialized in this function [-Wmaybe-uninitialized]
   cout << sum1 << sum2 << sum3;
   ~~~~~~~~~~~~~~~~~~~~~^~~~~~~
/in/foo.cc:46:19: warning: 'sum2' may be used uninitialized in this function [-Wmaybe-uninitialized]
   cout << sum1 << sum2 << sum3;
                   ^~~~
/in/foo.cc:46:11: warning: 'sum1' may be used uninitialized in this function [-Wmaybe-uninitialized]
   cout << sum1 << sum2 << sum3;
           ^~~~