foo.cc: In member function 'BigInt& BigInt::operator=(const BigInt&)':
foo.cc:57:2: warning: no return statement in function returning non-void [-Wreturn-type]
   56 |   memcpy(a,BI.a,sizeof(int)*MAX);
  +++ |+  return *this;
   57 |  }
      |  ^

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