Chapter 4 Standard Library Routine
219
4.2 Character Class Tests: <ctype.h>
For each function, the argument is a character, whose value must be EOF or representable
as an unsigned char, and the return value is an integer.
The functions return non-zero (true) if the argument c satisfies the condition described;
otherwise, zero is returned.
isalnum (c)
isalpha (c) or isdigit (c) is true
isalpha (c)
isupper (c) or islower (c) is true
iscntrl (c)
control character
isdigit (c)
decimal digit
isgraph (c)
printing character except space
islower (c)
lower-case letter
isprint (c)
printing character including space
ispunct (c)
printing character except space, letter and digit
isspace (c)
space, formfeed, newline, carriage return, tab, vertical tab
isupper (c)
upper-case letter
isxdigit (c)
hexadecimal digit
In addition, there are two functions that convert the case of letters:
int tolower (c)
convert c to lower-case
int toupper (c)
convert c to upper-case
Summary of Contents for Optimus R
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