/in/foo.cc: In member function 'BigInt BigInt::operator-(BigInt) const':
/in/foo.cc:123:78: warning: unused variable 'len' [-Wunused-variable]
   vector<int>::size_type lenA(num.size()), lenB(bInt.num.size()), lng, shrt, len;
                                                                              ^~~
/in/foo.cc: At global scope:
/in/foo.cc:385:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main()
      ^