/in/foo.cc: In function 'std::Bigint std::sub_number(Bigint&, Bigint&)':
/in/foo.cc:478:28: error: call of overloaded 'to_string(int&)' is ambiguous
  478 |           tmpx0 = to_string(*i);
      |                   ~~~~~~~~~^~~~
/in/foo.cc:100:13: note: candidate: 'std::string std::to_string(const Bigint&)'
  100 | std::string to_string(Bigint const &);
      |             ^~~~~~~~~
/in/foo.cc:458:20: note: candidate: 'std::string std::to_string(int)'
  458 | static std::string to_string(const int value)
      |                    ^~~~~~~~~
In file included from /usr/include/c++/12/string:53,
                 from /usr/include/c++/12/bits/locale_classes.h:40,
                 from /usr/include/c++/12/bits/ios_base.h:41,
                 from /usr/include/c++/12/ios:42,
                 from /usr/include/c++/12/istream:38,
                 from /usr/include/c++/12/sstream:38,
                 from /usr/include/c++/12/complex:45,
                 from /usr/include/c++/12/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/12/bits/stdc++.h:54,
                 from /in/foo.cc:1:
/usr/include/c++/12/bits/basic_string.h:4012:3: note: candidate: 'std::string std::__cxx11::to_string(int)'
 4012 |   to_string(int __val)
      |   ^~~~~~~~~
/usr/include/c++/12/bits/basic_string.h:4026:3: note: candidate: 'std::string std::__cxx11::to_string(unsigned int)'
 4026 |   to_string(unsigned __val)
      |   ^~~~~~~~~
/usr/include/c++/12/bits/basic_string.h:4037:3: note: candidate: 'std::string std::__cxx11::to_string(long int)'
 4037 |   to_string(long __val)
      |   ^~~~~~~~~
/usr/include/c++/12/bits/basic_string.h:4051:3: note: candidate: 'std::string std::__cxx11::to_string(long unsigned int)'
 4051 |   to_string(unsigned long __val)
      |   ^~~~~~~~~
/usr/include/c++/12/bits/basic_string.h:4062:3: note: candidate: 'std::string std::__cxx11::to_string(long long int)'
 4062 |   to_string(long long __val)
      |   ^~~~~~~~~
/usr/include/c++/12/bits/basic_string.h:4074:3: note: candidate: 'std::string std::__cxx11::to_string(long long unsigned int)'
 4074 |   to_string(unsigned long long __val)
      |   ^~~~~~~~~
/usr/include/c++/12/bits/basic_string.h:4085:3: note: candidate: 'std::string std::__cxx11::to_string(float)'
 4085 |   to_string(float __val)
      |   ^~~~~~~~~
/usr/include/c++/12/bits/basic_string.h:4094:3: note: candidate: 'std::string std::__cxx11::to_string(double)'
 4094 |   to_string(double __val)
      |   ^~~~~~~~~
/usr/include/c++/12/bits/basic_string.h:4103:3: note: candidate: 'std::string std::__cxx11::to_string(long double)'
 4103 |   to_string(long double __val)
      |   ^~~~~~~~~
/in/foo.cc:512:32: error: call of overloaded 'to_string(int&)' is ambiguous
  512 |               tmpx0 = to_string(*i);
      |                       ~~~~~~~~~^~~~
/in/foo.cc:100:13: note: candidate: 'std::string std::to_string(const Bigint&)'
  100 | std::string to_string(Bigint const &);
      |             ^~~~~~~~~
/in/foo.cc:458:20: note: candidate: 'std::string std::to_string(int)'
  458 | static std::string to_string(const int value)
      |                    ^~~~~~~~~
/usr/include/c++/12/bits/basic_string.h:4012:3: note: candidate: 'std::string std::__cxx11::to_string(int)'
 4012 |   to_string(int __val)
      |   ^~~~~~~~~
/usr/include/c++/12/bits/basic_string.h:4026:3: note: candidate: 'std::string std::__cxx11::to_string(unsigned int)'
 4026 |   to_string(unsigned __val)
      |   ^~~~~~~~~
/usr/include/c++/12/bits/basic_string.h:4037:3: note: candidate: 'std::string std::__cxx11::to_string(long int)'
 4037 |   to_string(long __val)
      |   ^~~~~~~~~
/usr/include/c++/12/bits/basic_string.h:4051:3: note: candidate: 'std::string std::__cxx11::to_string(long unsigned int)'
 4051 |   to_string(unsigned long __val)
      |   ^~~~~~~~~
/usr/include/c++/12/bits/basic_string.h:4062:3: note: candidate: 'std::string std::__cxx11::to_string(long long int)'
 4062 |   to_string(long long __val)
      |   ^~~~~~~~~
/usr/include/c++/12/bits/basic_string.h:4074:3: note: candidate: 'std::string std::__cxx11::to_string(long long unsigned int)'
 4074 |   to_string(unsigned long long __val)
      |   ^~~~~~~~~
/usr/include/c++/12/bits/basic_string.h:4085:3: note: candidate: 'std::string std::__cxx11::to_string(float)'
 4085 |   to_string(float __val)
      |   ^~~~~~~~~
/usr/include/c++/12/bits/basic_string.h:4094:3: note: candidate: 'std::string std::__cxx11::to_string(double)'
 4094 |   to_string(double __val)
      |   ^~~~~~~~~
/usr/include/c++/12/bits/basic_string.h:4103:3: note: candidate: 'std::string std::__cxx11::to_string(long double)'
 4103 |   to_string(long double __val)
      |   ^~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:877:18: error: no matching function for call to 'pow(std::Bigint&, std::Bigint&)'
  877 |         cout<<pow(a,n1)*pow(b,n2);
      |               ~~~^~~~~~
In file included from /usr/include/c++/12/valarray:603,
                 from /usr/include/x86_64-linux-gnu/c++/12/bits/stdc++.h:95:
/usr/include/c++/12/bits/valarray_after.h:549:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::_Pow, std::_Constant, std::_ValArray, _Tp, _Tp>, _Tp> std::pow(const typename valarray<_Tp>::value_type&, const valarray<_Tp>&)'
  549 | _DEFINE_EXPR_BINARY_FUNCTION(pow, struct std::_Pow)
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/12/bits/valarray_after.h:549:1: note:   template argument deduction/substitution failed:
/in/foo.cc:877:18: note:   'std::Bigint' is not derived from 'const std::valarray<_Tp>'
  877 |         cout<<pow(a,n1)*pow(b,n2);
      |               ~~~^~~~~~
/usr/include/c++/12/bits/valarray_after.h:549:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::_Pow, std::_ValArray, std::_Constant, _Tp, _Tp>, _Tp> std::pow(const valarray<_Tp>&, const typename valarray<_Tp>::value_type&)'
  549 | _DEFINE_EXPR_BINARY_FUNCTION(pow, struct std::_Pow)
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/12/bits/valarray_after.h:549:1: note:   template argument deduction/substitution failed:
/in/foo.cc:877:18: note:   'std::Bigint' is not derived from 'const std::valarray<_Tp>'
  877 |         cout<<pow(a,n1)*pow(b,n2);
      |               ~~~^~~~~~
/usr/include/c++/12/bits/valarray_after.h:549:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::_Pow, std::_ValArray, std::_ValArray, _Tp, _Tp>, _Tp> std::pow(const valarray<_Tp>&, const valarray<_Tp>&)'
  549 | _DEFINE_EXPR_BINARY_FUNCTION(pow, struct std::_Pow)
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/12/bits/valarray_after.h:549:1: note:   template argument deduction/substitution failed:
/in/foo.cc:877:18: note:   'std::Bigint' is not derived from 'const std::valarray<_Tp>'
  877 |         cout<<pow(a,n1)*pow(b,n2);
      |               ~~~^~~~~~
/usr/include/c++/12/bits/valarray_after.h:549:1: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::_Pow, std::_Constant, std::_Expr, typename _Dom::value_type, _Dom>, typename _Dom::value_type> std::pow(const typename _Dom::value_type&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  549 | _DEFINE_EXPR_BINARY_FUNCTION(pow, struct std::_Pow)
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/12/bits/valarray_after.h:549:1: note:   template argument deduction/substitution failed:
/in/foo.cc:877:18: note:   'std::Bigint' is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
  877 |         cout<<pow(a,n1)*pow(b,n2);
      |               ~~~^~~~~~
/usr/include/c++/12/bits/valarray_after.h:549:1: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::_Pow, std::_Expr, std::_Constant, _Dom, typename _Dom::value_type>, typename _Dom::value_type> std::pow(const _Expr<_Dom1, typename _Dom1::value_type>&, const typename _Dom::value_type&)'
  549 | _DEFINE_EXPR_BINARY_FUNCTION(pow, struct std::_Pow)
      | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/12/bits/valarray_after.h:549:1: note:   template argument deduction/substitution failed:
/in/foo.cc:877:18: note:   'std::Bigint' is not derived from 'const std::_Expr<_Dom1