std::islower(std::locale) (3) - Linux Manuals

std::islower(std::locale): std::islower(std::locale)

NAME

std::islower(std::locale) - std::islower(std::locale)

Synopsis

Defined in header <locale>
template< class charT >
bool islower( charT ch, const locale& loc );

Checks if the given character is classified as a lowercase alphabetic character by the given locale's std::ctype facet.

Parameters

ch - character
loc - locale

Return value

Returns true if the character is classified as lowercase, false otherwise.

Possible implementation

  template< class charT >
  bool islower( charT ch, const std::locale& loc ) {
      return std::use_facet<std::ctype<charT>>(loc).is(std::ctype_base::lower, ch);
  }

Example

Demonstrates the use of islower() with different locales (OS-specific).
// Run this code

  #include <iostream>
  #include <locale>
  int main()
  {
      const wchar_t c = L'\u03c0'; // greek small letter pi

      std::locale loc1("C");
      std::cout << "islower('π', C locale) returned "
                 << std::boolalpha << std::islower(c, loc1) << '\n';

      std::locale loc2("en_US.UTF8");
      std::cout << "islower('π', Unicode locale) returned "
                << std::boolalpha << std::islower(c, loc2) << '\n';
  }

Output:

  islower('π', C locale) returned false
  islower('π', Unicode locale) returned true