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Functions

Behavior of these functions is controlled by the current locale (use setlocale() to change the current locale). In the C locale, or in a locale where character type information is not defined, characters are classified according to the rules of the US-ASCII 7-bit coded character set.

bool isalnum(int c)

tests for any character for which isalpha() or isdigit() is true (letter or digit).

bool isdigit(int c)

tests for any decimal-digit character.

bool isprint(int c)

tests for any character for which ispunct(), isupper(), islower(), isdigit(), and the space character ("") is true.

bool isupper(int c)

tests for any character that is an upper-case letter.

int tolower(int c)

 

bool isalpha(int c)

tests for any character for which isupper() or islower() is true.

bool isgraph(int c)

tests for any character for which ispunct(), isupper(), islower(), and isdigit() is true.

bool ispunct(int c)

tests for any printing character which is neither a space ("") nor a character for which isalnum() or iscntrl() is true (i.e., punctuation).

bool isxdigit(int c)

tests for any hexadecimal-digit character.

int toupper(int c)

 

bool iscntrl(int c)

tests for any "control character'' as defined by the character set.

bool islower(int c)

tests for any character that is a lower-case letter.

bool isspace(int c)

tests for any space, tab, carriage-return, newline, vertical-tab or form-feed (standard white-space characters).

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