/in/foo.cc: In function 'int dight(long long int, long long int)':
/in/foo.cc:12:9: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]
  return ret;
         ^~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:16:18: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]
  cout<<dight(n,k);
                  ^