foo.cc:13:10: error: ISO C++ forbids declaration of 'Initial' with no type [-fpermissive]
   13 |  Initial(){ for(int i = 0;i<10000;i++) v.push_back(0); }
      |          ^
foo.cc: In member function 'int BigInt::Initial()':
foo.cc:13:56: warning: no return statement in function returning non-void [-Wreturn-type]
   13 |  Initial(){ for(int i = 0;i<10000;i++) v.push_back(0); }
      |                                                        ^
foo.cc: In member function 'BigInt& BigInt::operator=(const BigInt&)':
foo.cc:51:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   51 |   for(int i = 0;i<b.v.size();i++)
      |                 ~^~~~~~~~~~~

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