std::islower

int islower( int ch );

Checks if the given character is classified as a lowercase character according to the current C locale. In the default "C" locale, islower returns true only for the lowercase letters (abcdefghijklmnopqrstuvwxyz).

If islower returns true, it is guaranteed that iscntrl, isdigit, ispunct, and isspace return false for the same character in the same C locale.

The behavior is undefined if the value of ch is not representable as unsigned char and is not equal to EOF.

Parameters

Return value

Non-zero value if the character is a lowercase letter, zero otherwise.

Example

#include <iostream>
#include <cctype>
#include <clocale>
 
int main()
{
    unsigned char c = '\xe5'; // letter å in ISO-8859-1
 
    std::cout << "islower(\'\\xe5\', default C locale) returned "
               << std::boolalpha << (bool)std::islower(c) << '\n';
 
    std::setlocale(LC_ALL, "en_GB.iso88591");
    std::cout << "islower(\'\\xe5\', ISO-8859-1 locale) returned "
              << std::boolalpha << (bool)std::islower(c) << '\n';
 
}

islower('\xe5', default C locale) returned false
islower('\xe5', ISO-8859-1 locale) returned true

See also