std::ctype - cppreference.com (original) (raw)

| | | | | ------------------------------------- | | | | template< class CharT > class ctype; | | |

Class ctype encapsulates character classification features. All stream input operations performed through std::basic_istream<CharT> use the std::ctype<CharT> of the locale imbued in the stream to identify whitespace characters for input tokenization. Stream output operations apply std::ctype<CharT>::widen() to narrow-character arguments prior to output.

Inheritance diagram

Contents

• 1 Specializations
• 2 Nested types
• 3 Data members
• 4 Member functions
• 5 Protected member functions
• 6 Inherited from std::ctype_base
  • 6.1 Nested types
  • 6.2 Member constants
  • 6.3 Example
  • 6.4 See also

[edit] Specializations

The standard library is guaranteed to provide the following specializations (they are required to be implemented by any locale object):

[edit] Nested types

[edit] Data members

[edit] Member functions

[edit] Protected member functions

Inherited from std::ctype_base

Nested types

Member constants

[edit] Example

The following example demonstrates modification of a ctype other than ctype<char> to tokenize a CSV file:

#include #include #include   struct csv_whitespace : std::ctype { bool do_is(mask m, char_type c) const { if ((m & space) && c == L' ') return false; // space will NOT be classified as whitespace   if ((m & space) && c == L',') return true; // comma will be classified as whitespace   return ctype::do_is(m, c); // leave the rest to the base class } };   int main() { std::wstring in = L"Column 1,Column 2,Column 3\n123,456,789"; std::wstring token;   std::wcout << "default locale:\n"; std::wistringstream s1(in); while (s1 >> token) std::wcout << " " << token << '\n';   std::wcout << "locale with modified ctype:\n"; std::wistringstream s2(in); csv_whitespace* my_ws = new csv_whitespace; s2.imbue(std::locale(s2.getloc(), my_ws)); while (s2 >> token) std::wcout << " " << token << '\n'; }

Output:

default locale: Column 1,Column 2,Column 3 123,456,789 locale with modified ctype: Column 1 Column 2 Column 3 123 456 789

[edit] See also

| | specialization of std::ctype for type char (class template specialization) [edit] | | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | defines character classification categories (class) [edit] | | | represents the system-supplied std::ctype for the named locale (class template) [edit] |