Language: C++

#include <iostream>
#include <cstring>
#include <cctype>

#define MAX_LEN (1200)

using namespace std;

int main()
{    
    char* str = new char[MAX_LEN + 1];
   
    do {
        getline(cin, str);
    } while (strlen(str) > MAX_LEN);

    for (int i = 0; str[i] != '\0'; i++) {
         if (str[i] >= 'A' && str[i] <= 'Z') {
	     str[i] = tolower(str[i]);
	 } else if (str[i] >= 'a' && str[i] <= 'z') {
	     str[i] = toupper(str[i]);
         }
    }

    cout << str << endl;
   
    delete[] str;
   
    return (0);
} 

    
    

Compiler output:
a.cc: In function 'int main()':
a.cc:14:16: error: no matching function for call to 'getline(std::istream&, char*&)'
   14 |         getline(cin, str);
      |         ~~~~~~~^~~~~~~~~~
In file included from /usr/include/c++/14/string:55,
                 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/bits/basic_string.tcc:907:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::basic_istream<_CharT, _Traits>& std::getline(basic_istream<_CharT, _Traits>&, __cxx11::basic_string<_CharT, _Traits, _Allocator>&, _CharT)'
  907 |     getline(basic_istream<_CharT, _Traits>& __in,
      |     ^~~~~~~
/usr/include/c++/14/bits/basic_string.tcc:907:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/string:54:
/usr/include/c++/14/bits/basic_string.h:4117:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::basic_istream<_CharT, _Traits>& std::getline(basic_istream<_CharT, _Traits>&, __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 4117 |     getline(basic_istream<_CharT, _Traits>& __is,
      |     ^~~~~~~
/usr/include/c++/14/bits/basic_string.h:4117:5: note:   template argument deduction/substitution failed:
a.cc:14:16: note:   mismatched types 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'char*'
   14 |         getline(cin, str);
      |         ~~~~~~~^~~~~~~~~~
/usr/include/c++/14/bits/basic_string.h:4125:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::basic_istream<_CharT, _Traits>& std::getline(basic_istream<_CharT, _Traits>&&, __cxx11::basic_string<_CharT, _Traits, _Allocator>&, _CharT)'
 4125 |     getline(basic_istream<_CharT, _Traits>&& __is,
      |     ^~~~~~~
/usr/include/c++/14/bits/basic_string.h:4125:5: note:   candidate expects 3 arguments, 2 provided
/usr/include/c++/14/bits/basic_string.h:4132:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> std::basic_istream<_CharT, _Traits>& std::getline(basic_istream<_CharT, _Traits>&&, __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 4132 |     getline(basic_istream<_CharT, _Traits>&& __is,
      |     ^~~~~~~
/usr/include/c++/14/bits/basic_string.h:4132:5: note:   template argument deduction/substitution failed:
a.cc:14:16: note:   mismatched types 'std::__cxx11::basic_string<_CharT, _Traits, _Allocator>' and 'char*'
   14 |         getline(cin, str);
      |         ~~~~~~~^~~~~~~~~~
In file included from /usr/include/c++/14/cstdio:42,
                 from /usr/include/c++/14/ext/string_conversions.h:45,
                 from /usr/include/c++/14/bits/basic_string.h:4154:
/usr/include/stdio.h:697:18: note: candidate: '__ssize_t getline(char**, size_t*, FILE*)'
  697 | extern __ssize_t getline (char **__restrict __lineptr,
      |                  ^~~~~~~
/usr/include/stdio.h:697:18: note:   candidate expects 3 arguments, 2 provided