Language: C++

#include <iostream>
#include <vector>
#include <algorithm>
#include <math.h>
#include <climits>
#include <string>

using namespace std;


int main() {
  int N, K;
  string S;
  cin >> N >> K >> S;
  
  cout << (( 1==K? "" : S.substr(0, K-1) ) << tolower(S[K-1]) << ( (N==K? "" : S.substr(K) ) << endl;

  return 0;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:16:44: error: no match for 'operator<<' (operand types are 'std::__cxx11::basic_string<char>' and 'int')
   16 |   cout << (( 1==K? "" : S.substr(0, K-1) ) << tolower(S[K-1]) << ( (N==K? "" : S.substr(K) ) << endl;
      |            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^~ ~~~~~~~~~~~~~~~
      |                  |                                   |
      |                  std::__cxx11::basic_string<char>    int
In file included from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54,
                 from /usr/include/c++/14/bits/locale_classes.h:40,
                 from /usr/include/c++/14/bits/ios_base.h:41,
                 from /usr/include/c++/14/ios:44,
                 from /usr/include/c++/14/ostream:40,
                 from /usr/include/c++/14/iostream:41,
                 from a.cc:1:
/usr/include/c++/14/string_view:763:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, basic_string_view<_CharT, _Traits>)'
  763 |     operator<<(basic_ostream<_CharT, _Traits>& __os,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:763:5: note:   template argument deduction/substitution failed:
a.cc:16:61: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_ostream<_CharT, _Traits>'
   16 |   cout << (( 1==K? "" : S.substr(0, K-1) ) << tolower(S[K-1]) << ( (N==K? "" : S.substr(K) ) << endl;
      |                                                             ^
/usr/include/c++/14/bits/basic_string.h:4077:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 4077 |     operator<<(basic_ostream<_CharT, _Traits>& __os,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:4077:5: note:   template argument deduction/substitution failed:
a.cc:16:61: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_ostream<_CharT, _Traits>'
   16 |   cout << (( 1==K? "" : S.substr(0, K-1) ) << tolower(S[K-1]) << ( (N==K? "" : S.substr(K) ) << endl;
      |                                                             ^
In file included from /usr/include/c++/14/bits/memory_resource.h:38,
                 from /usr/include/c++/14/string:68:
/usr/include/c++/14/cstddef:125:5: note: candidate: 'template<class _IntegerType> constexpr std::__byte_op_t<_IntegerType> std::operator<<(byte, _IntegerType)'
  125 |     operator<<(byte __b, _IntegerType __shift) noexcept
      |     ^~~~~~~~
/usr/include/c++/14/cstddef:125:5: note:   template argument deduction/substitution failed:
a.cc:16:18: note:   cannot convert '((1 == K) ? std::__cxx11::basic_string<char>(((const char*)""), std::allocator<char>()) : std::__cxx11::basic_string<_CharT, _Traits, _Alloc>::substr(size_type, size_type) const [with _CharT = char; _Traits = std::char_traits<char>; _Alloc = std::allocator<char>; size_type = long unsigned int](0, ((std::__cxx11::basic_string<char>::size_type)(K - 1))))' (type 'std::__cxx11::basic_string<char>') to type 'std::byte'
   16 |   cout << (( 1==K? "" : S.substr(0, K-1) ) << tolower(S[K-1]) << ( (N==K? "" : S.substr(K) ) << endl;
      |            ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/bits/ios_base.h:46:
/usr/include/c++/14/system_error:339:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, const error_code&)'
  339 |     operator<<(basic_ostream<_CharT, _Traits>& __os, const error_code& __e)
      |     ^~~~~~~~
/usr/include/c++/14/system_error:339:5: note:   template argument deduction/substitution failed:
a.cc:16:61: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_ostream<_CharT, _Traits>'
   16 |   cout << (( 1==K? "" : S.substr(0, K-1) ) << tolower(S[K-1]) << ( (N==K? "" : S.substr(K) ) << endl;
      |                                                             ^
/usr/include/c++/14/ostream:563:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, _CharT)'
  563 |     operator<<(basic_ostream<_CharT, _Traits>& __out, _CharT __c)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:563:5: note:   template argument deduction/substitution failed:
a.cc:16:61: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_ostream<_CharT, _Traits>'
   16 |   cout << (( 1==K? "" : S.substr(0, K-1) ) << tolower(S[K-1]) << ( (N==K? "" : S.substr(K) ) << endl;
      |                                                             ^
/usr/include/c++/14/ostream:573:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, char)'
  573 |     operator<<(basic_ostream<_CharT, _Traits>& __out, char __c)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:573:5: note:   template argument deduction/substitution failed:
a.cc:16:61: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_ostream<_CharT, _Traits>'
   16 |   cout << (( 1==K? "" : S.substr(0, K-1) ) << tolower(S[K-1]) << ( (N==K? "" : S.substr(K) ) << endl;
      |                                                             ^
/usr/include/c++/14/ostream:579:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(basic_ostream<char, _Traits>&, char)'
  579 |     operator<<(basic_ostream<char, _Traits>& __out, char __c)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:579:5: note:   template argument deduction/substitution failed:
a.cc:16:61: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_ostream<char, _Traits>'
   16 |   cout << (( 1==K? "" : S.substr(0, K-1) ) << tolower(S[K-1]) << ( (N==K? "" : S.substr(K) ) << endl;
      |                                                             ^
/usr/include/c++/14/ostream:590:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(basic_ostream<char, _Traits>&, signed char)'
  590 |     operator<<(basic_ostream<char, _Traits>& __out, signed char __c)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:590:5: note:   template argument deduction/substitution failed:
a.cc:16:61: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_ostream<char, _Traits>'
   16 |   cout << (( 1==K? "" : S.substr(0, K-1) ) << tolower(S[K-1]) << ( (N==K? "" : S.substr(K) ) << endl;
      |                                                             ^
/usr/include/c++/14/ostream:595:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(basic_ostream<char, _Traits>&, unsigned char)'
  595 |     operator<<(basic_ostream<char, _Traits>& __out, unsigned char __c)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:595:5: note:   template argument deduction/substitution failed:
a.cc:16:61: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_ostream<char, _Traits>'
   16 |   cout << (( 1==K? "" : S.substr(0, K-1) ) << tolower(S[K-1]) << ( (N==K? "" : S.substr(K) ) << endl;
      |                                                             ^
/usr/include/c++/14/ostream:654:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, const _CharT*)'
  654 |     operator<<(basic_ostream<_CharT, _Traits>& __out, const _CharT* __s)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:654:5: note:   template argument deduction/substitution failed:
a.cc:16:61: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_ostream<_CharT, _Traits>'
   16 |   cout << (( 1==K? "" : S.substr(0, K-1) ) << tolower(S[K-1]) << ( (N==K? "" : S.substr(K) ) << endl;
      |                                                             ^
In file included from /usr/include/c++/14/ostream:1022:
/usr/include/c++/14/bits/ostream.tcc:307:5: note: candidate: 'template<class _CharT, class _Traits> std::basic_ostream<_CharT, _Traits>& std::operator<<(basic_ostream<_CharT, _Traits>&, const char*)'
  307 |     operator<<(basic_ostream<_CharT, _Traits>& __out, const char* __s)
      |     ^~~~~~~~
/usr/include/c++/14/bits/ostream.tcc:307:5: note:   template argument deduction/substitution failed:
a.cc:16:61: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_ostream<_CharT, _Traits>'
   16 |   cout << (( 1==K? "" : S.substr(0, K-1) ) << tolower(S[K-1]) << ( (N==K? "" : S.substr(K) ) << endl;
      |                                                             ^
/usr/include/c++/14/ostream:671:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(basic_ostream<char, _Traits>&, const char*)'
  671 |     operator<<(basic_ostream<char, _Traits>& __out, const char* __s)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:671:5: note:   template argument deduction/substitution failed:
a.cc:16:61: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_ostream<char, _Traits>'
   16 |   cout << (( 1==K? "" : S.substr(0, K-1) ) << tolower(S[K-1]) << ( (N==K? "" : S.substr(K) ) << endl;
      |                                                             ^
/usr/include/c++/14/ostream:684:5: note: candidate: 'template<class _Traits> std::basic_ostream<char, _Traits>& std::operator<<(basic_ostream<char, _Traits>&, const signed char*)'
  684 |     operator<<(basic_ostream<char, _Traits>& __out, const signed char* __s)
      |     ^~~~~~~~
/usr/include/c++/14/ostream:684:5: note:   template argument deduction/substitution failed:
a.cc:16:61: note:   'std::__cxx11::basic_string<char>' is not derived from 'std::basic_ostream<char, _Traits>'
   16 |   cout << (( 1==K? "" : S.substr(0, K-1) ) << tolower(S[K-1]) << ( (N==K? "" : S.substr(K) ) << endl;
      |                                                             ^
/usr/include/c++/14/ostream:689:5: note: candidate: 'te