Character Classification and Conversion

#include <ctype.h>

int isalnum(int c) - True if c is alphanumeric.

int isalpha(int c) - True if c is a letter.

int isascii(int c) - True if c is ASCII .

int iscntrl(int c) - True if c is a control character.

int isdigit(int c) - True if c is a decimal digit.

int isgraph(int c) - True if c is a graphical character.

int islower(int c) - True if c is a lowercase letter.

int isprint(int c) - True if c is a printable character.

int ispunct(int c) - True if c is a punctuation character.

int isspace(int c) - True if c is a space character.

int isupper(int c) - True if c is an uppercase letter.

int isxdigit(int c) - True if c is a hexadecimal digit.

int toascii(int c) - Convert c to ASCII .

tolower(int c) - Convert c to lowercase.

int toupper(int c) - Convert c to uppercase.