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 int isalpha(int c)

Description

The isalpha() function tests for any character for which isupper() or islower() is true, or any character that is one of an implementation-defined set of characters for which none of iscntrl(), isdigit(), ispunct(), or isspace() is true. In the C locale, isalpha() returns true only for the characters for which isupper() or islower() is true.

The behavior of the isalpha() function is affected by the current locale. To modify the behavior, change the LC_CTYPE category in setlocale(), that is, setlocale(LC_CTYPE, newlocale). In the C locale or in a locale where character type information is not defined, characters are classified according to the rules of the U.S. ASCII 7-bit coded character set.

Parameters

• c
  Is an integer whose value is representable as an unsigned char or the value of the macro EOF.

Return Values

The isalpha() function returns non-zero for true and zero for false. If the parameter is not in the domain of the function, the return result is undefined.

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