Language: C++

#include <bits/stdc++.h>
using namespace std;

int main() {
  std::string str1;
  std::string str2;
  std::string str3;
  cin >> str1;
  str2 = str1;
  str3 = str1;
   str2.erase(str2.begin() + 2);
   str2.erase(str2.begin() + 2);
   str3.erase(str3.begin() + 1);
   str3.erase(str3.begin() + 0);
    cout << str2  << str3 << endl;
  
  if (str2 = '00'||str3 = '00') {
    cout << "NA" << endl;
  }
  
  
  int str32;
  str32 = stoi(str3);
  int str21
  str21 = stoi(str2);
    if (str32 < 13) {
    cout << "AMBIGUOUS" << endl;
  }
  //MMは12月まで。
  else{
    cout << "YYMM" << endl;
  }
  
}


Compiler output:
a.cc:17:14: warning: multi-character character constant [-Wmultichar]
   17 |   if (str2 = '00'||str3 = '00') {
      |              ^~~~
a.cc:17:27: warning: multi-character character constant [-Wmultichar]
   17 |   if (str2 = '00'||str3 = '00') {
      |                           ^~~~
a.cc: In function 'int main()':
a.cc:17:18: error: no match for 'operator||' (operand types are 'int' and 'std::string' {aka 'std::__cxx11::basic_string<char>'})
   17 |   if (str2 = '00'||str3 = '00') {
      |              ~~~~^~~~~~
      |              |     |
      |              int   std::string {aka std::__cxx11::basic_string<char>}
a.cc:17:18: note: candidate: 'operator||(bool, bool)' (built-in)
   17 |   if (str2 = '00'||str3 = '00') {
      |              ~~~~^~~~~~
a.cc:17:18: note:   no known conversion for argument 2 from 'std::string' {aka 'std::__cxx11::basic_string<char>'} to 'bool'
In file included from /usr/include/c++/14/valarray:605,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:166,
                 from a.cc:1:
/usr/include/c++/14/bits/valarray_after.h:416:5: note: candidate: 'template<class _Dom1, class _Dom2> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_Expr, std::_Expr, _Dom1, _Dom2>, typename std::__fun<std::__logical_or, typename _Dom1::value_type>::result_type> std::operator||(const _Expr<_Dom1, typename _Dom1::value_type>&, const _Expr<_Dom2, typename _Dom2::value_type>&)'
  416 |     _DEFINE_EXPR_BINARY_OPERATOR(||, struct std::__logical_or)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note:   template argument deduction/substitution failed:
a.cc:17:20: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'int'
   17 |   if (str2 = '00'||str3 = '00') {
      |                    ^~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_Expr, std::_Constant, _Dom, typename _Dom::value_type>, typename std::__fun<std::__logical_or, typename _Dom1::value_type>::result_type> std::operator||(const _Expr<_Dom1, typename _Dom1::value_type>&, const typename _Dom::value_type&)'
  416 |     _DEFINE_EXPR_BINARY_OPERATOR(||, struct std::__logical_or)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note:   template argument deduction/substitution failed:
a.cc:17:20: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'int'
   17 |   if (str2 = '00'||str3 = '00') {
      |                    ^~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_Constant, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__logical_or, typename _Dom1::value_type>::result_type> std::operator||(const typename _Dom::value_type&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  416 |     _DEFINE_EXPR_BINARY_OPERATOR(||, struct std::__logical_or)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note:   template argument deduction/substitution failed:
a.cc:17:20: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   17 |   if (str2 = '00'||str3 = '00') {
      |                    ^~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_Expr, std::_ValArray, _Dom, typename _Dom::value_type>, typename std::__fun<std::__logical_or, typename _Dom1::value_type>::result_type> std::operator||(const _Expr<_Dom1, typename _Dom1::value_type>&, const valarray<typename _Dom::value_type>&)'
  416 |     _DEFINE_EXPR_BINARY_OPERATOR(||, struct std::__logical_or)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note:   template argument deduction/substitution failed:
a.cc:17:20: note:   mismatched types 'const std::_Expr<_Dom1, typename _Dom1::value_type>' and 'int'
   17 |   if (str2 = '00'||str3 = '00') {
      |                    ^~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note: candidate: 'template<class _Dom> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_ValArray, std::_Expr, typename _Dom::value_type, _Dom>, typename std::__fun<std::__logical_or, typename _Dom1::value_type>::result_type> std::operator||(const valarray<typename _Dom::value_type>&, const _Expr<_Dom1, typename _Dom1::value_type>&)'
  416 |     _DEFINE_EXPR_BINARY_OPERATOR(||, struct std::__logical_or)
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/valarray_after.h:416:5: note:   template argument deduction/substitution failed:
a.cc:17:20: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::_Expr<_Dom1, typename _Dom1::value_type>'
   17 |   if (str2 = '00'||str3 = '00') {
      |                    ^~~~
/usr/include/c++/14/valarray:1207:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_ValArray, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__logical_or, _Tp>::result_type> std::operator||(const valarray<_Tp>&, const valarray<_Tp>&)'
 1207 | _DEFINE_BINARY_OPERATOR(||, __logical_or)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1207:1: note:   template argument deduction/substitution failed:
a.cc:17:20: note:   mismatched types 'const std::valarray<_Tp>' and 'int'
   17 |   if (str2 = '00'||str3 = '00') {
      |                    ^~~~
/usr/include/c++/14/valarray:1207:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_ValArray, std::_Constant, _Tp, _Tp>, typename std::__fun<std::__logical_or, _Tp>::result_type> std::operator||(const valarray<_Tp>&, const typename valarray<_Tp>::value_type&)'
 1207 | _DEFINE_BINARY_OPERATOR(||, __logical_or)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1207:1: note:   template argument deduction/substitution failed:
a.cc:17:20: note:   mismatched types 'const std::valarray<_Tp>' and 'int'
   17 |   if (str2 = '00'||str3 = '00') {
      |                    ^~~~
/usr/include/c++/14/valarray:1207:1: note: candidate: 'template<class _Tp> std::_Expr<std::__detail::_BinClos<std::__logical_or, std::_Constant, std::_ValArray, _Tp, _Tp>, typename std::__fun<std::__logical_or, _Tp>::result_type> std::operator||(const typename valarray<_Tp>::value_type&, const valarray<_Tp>&)'
 1207 | _DEFINE_BINARY_OPERATOR(||, __logical_or)
      | ^~~~~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/valarray:1207:1: note:   template argument deduction/substitution failed:
a.cc:17:20: note:   'std::string' {aka 'std::__cxx11::basic_string<char>'} is not derived from 'const std::valarray<_Tp>'
   17 |   if (str2 = '00'||str3 = '00') {
      |                    ^~~~
a.cc:25:3: error: expected initializer before 'str21'
   25 |   str21 = stoi(str2);
      |   ^~~~~