foo.cc: In constructor 'BigInt::BigInt(std::string)':
foo.cc:23:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |   for(int j=0; j<s.size(); j++)
      |                ~^~~~~~~~~
In file included from /usr/include/string.h:495,
                 from /usr/include/c++/9/cstring:42,
                 from foo.cc:3:
In function 'void* memset(void*, int, size_t)',
    inlined from 'BigInt BigInt::operator+(const BigInt&)' at foo.cc:63:9,
    inlined from 'void Test3()' at foo.cc:212:19:
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:71:33: warning: 'void* __builtin___memset_chk(void*, int, long unsigned int, long unsigned int)' offset [405, 1000] from the object at 'ansss' is out of the bounds of referenced subobject 'BigInt::a' with type 'int [101]' at offset 0 [-Warray-bounds]
   71 |   return __builtin___memset_chk (__dest, __ch, __len, __bos0 (__dest));
      |          ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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