Language: C++

#include <iostream>
const int ASCII = 26;
using namespace std;

int main(){
	char ch;
	int charcnt[ASCII];

	while (cin >> ch){
		cin -= 'a';
		if((cin >= 0) && (cin < ASCII)){
			charcnt[cin]++;
		}
	}
	for(int i = 0; i < ASCII; i++){
		ch = i + 'a';
		cout << ch << " : " << charcnt[cin] << "\n"
	}
	cout << flush;

	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:10:21: error: no match for 'operator-=' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'char')
   10 |                 cin -= 'a';
      |                 ~~~~^~~~~~
a.cc:11:25: error: no match for 'operator>=' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'int')
   11 |                 if((cin >= 0) && (cin < ASCII)){
      |                     ~~~ ^~ ~
      |                     |      |
      |                     |      int
      |                     std::istream {aka std::basic_istream<char>}
a.cc:11:25: note: candidate: 'operator>=(int, int)' (built-in)
   11 |                 if((cin >= 0) && (cin < ASCII)){
      |                     ~~~~^~~~
a.cc:11:25: note:   no known conversion for argument 1 from 'std::istream' {aka 'std::basic_istream<char>'} to 'int'
In file included from /usr/include/c++/14/string:48,
                 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/stl_iterator.h:476:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator>=(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  476 |     operator>=(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:476:5: note:   template argument deduction/substitution failed:
a.cc:11:28: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'const std::reverse_iterator<_Iterator>'
   11 |                 if((cin >= 0) && (cin < ASCII)){
      |                            ^
/usr/include/c++/14/bits/stl_iterator.h:520:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator>=(const reverse_iterator<_Iterator>&, const reverse_iterator<_IteratorR>&)'
  520 |     operator>=(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:520:5: note:   template argument deduction/substitution failed:
a.cc:11:28: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'const std::reverse_iterator<_Iterator>'
   11 |                 if((cin >= 0) && (cin < ASCII)){
      |                            ^
/usr/include/c++/14/bits/stl_iterator.h:1724:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator>=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorR>&)'
 1724 |     operator>=(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1724:5: note:   template argument deduction/substitution failed:
a.cc:11:28: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'const std::move_iterator<_IteratorL>'
   11 |                 if((cin >= 0) && (cin < ASCII)){
      |                            ^
/usr/include/c++/14/bits/stl_iterator.h:1781:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator>=(const move_iterator<_IteratorL>&, const move_iterator<_IteratorL>&)'
 1781 |     operator>=(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:1781:5: note:   template argument deduction/substitution failed:
a.cc:11:28: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'const std::move_iterator<_IteratorL>'
   11 |                 if((cin >= 0) && (cin < ASCII)){
      |                            ^
In file included from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/string:51:
/usr/include/c++/14/bits/stl_pair.h:1070:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator>=(const pair<_T1, _T2>&, const pair<_T1, _T2>&)'
 1070 |     operator>=(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_pair.h:1070:5: note:   template argument deduction/substitution failed:
a.cc:11:28: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'const std::pair<_T1, _T2>'
   11 |                 if((cin >= 0) && (cin < ASCII)){
      |                            ^
In file included from /usr/include/c++/14/bits/basic_string.h:47,
                 from /usr/include/c++/14/string:54:
/usr/include/c++/14/string_view:739:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator>=(basic_string_view<_CharT, _Traits>, basic_string_view<_CharT, _Traits>)'
  739 |     operator>=(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:739:5: note:   template argument deduction/substitution failed:
a.cc:11:28: note:   'std::basic_istream<char>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   11 |                 if((cin >= 0) && (cin < ASCII)){
      |                            ^
/usr/include/c++/14/string_view:746:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator>=(basic_string_view<_CharT, _Traits>, __type_identity_t<basic_string_view<_CharT, _Traits> >)'
  746 |     operator>=(basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:746:5: note:   template argument deduction/substitution failed:
a.cc:11:28: note:   'std::basic_istream<char>' is not derived from 'std::basic_string_view<_CharT, _Traits>'
   11 |                 if((cin >= 0) && (cin < ASCII)){
      |                            ^
/usr/include/c++/14/string_view:754:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator>=(__type_identity_t<basic_string_view<_CharT, _Traits> >, basic_string_view<_CharT, _Traits>)'
  754 |     operator>=(__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
      |     ^~~~~~~~
/usr/include/c++/14/string_view:754:5: note:   template argument deduction/substitution failed:
a.cc:11:28: note:   mismatched types 'std::basic_string_view<_CharT, _Traits>' and 'int'
   11 |                 if((cin >= 0) && (cin < ASCII)){
      |                            ^
/usr/include/c++/14/bits/basic_string.h:3997:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator>=(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 3997 |     operator>=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:3997:5: note:   template argument deduction/substitution failed:
a.cc:11:28: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   11 |                 if((cin >= 0) && (cin < ASCII)){
      |                            ^
/usr/include/c++/14/bits/basic_string.h:4011:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator>=(const __cxx11::basic_string<_CharT, _Traits, _Allocator>&, const _CharT*)'
 4011 |     operator>=(const basic_string<_CharT, _Traits, _Alloc>& __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:4011:5: note:   template argument deduction/substitution failed:
a.cc:11:28: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'const std::__cxx11::basic_string<_CharT, _Traits, _Allocator>'
   11 |                 if((cin >= 0) && (cin < ASCII)){
      |                            ^
/usr/include/c++/14/bits/basic_string.h:4024:5: note: candidate: 'template<class _CharT, class _Traits, class _Alloc> bool std::operator>=(const _CharT*, const __cxx11::basic_string<_CharT, _Traits, _Allocator>&)'
 4024 |     operator>=(const _CharT* __lhs,
      |     ^~~~~~~~
/usr/include/c++/14/bits/basic_string.h:4024:5: note:   template argument deduction/substitution failed:
a.cc:11:28: note:   mismatched types 'const _CharT*' and 'std::basic_istream<char>'
   11 |                 if((cin >= 0) && (cin < ASCII)){
      |                            ^
In file included from /usr/include/c++/14/bits/memory_resource.h:47,
                 from /usr/include/c++/14/string:68:
/usr/include/c++/14/tuple:2631:5: note: candidate: 'template<class ... _TElements, class ... _UElements> constexpr bool std::operator>=(const tuple<_UTypes ...>&, const tuple<_Elements ...>&)'
 2631 |     operator>=(const tuple<_TElements...>& __t,
      |     ^~~~~~~~
/usr/include/c++/14/tuple:2631:5: note:   template argument deduction/substitution failed:
a.cc:11:28: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'const std::tuple<_UTypes ...>'
   11 |                 if((cin >= 0) && (cin < ASCII)){
      |                            ^
a.cc:11:39: error: no match for 'operator<' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'const int')
   11 |                 if((cin >= 0) && (cin < ASCII)){
      |                                   ~~~ ^ ~~~~~
      |                                   |     |
      |                                   |     const int
      |                                   std::istream {aka std::basic_istream<char>}
a.cc:11:39: note: candidate: 'operator<(int, int)' (built-in)
   11 |                 if((cin >= 0) && (cin < ASCII)){
      |                                   ~~~~^~~~~~~
a.cc:11:39: note:   no known conversion for argument 1 from 'std::istream' {aka 'std::basic_istream<char>'} to 'int'
/usr/include/c++/14/bits/stl_iterator.h:448:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator<(const reverse_iterator<_Iterator>&, const reverse_iterator<_Iterator>&)'
  448 |     operator<(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/14/bits/stl_iterator.h:448:5: note:   template argument deduction/substitution failed:
a.cc:11:41: note:   'std::istream' {aka 'std::basic_istream<char>'} is not derived from 'const std::reverse_iterator<_Iterator>'
   11 |                 if((cin >= 0) && (cin < ASCII)){
      |