Description
These macros, defined in ctype.h, test the supplied character for membership in one of several over-
lapping groups of characters. Note that all except isascii() are defined for c, if isascii(c) is true or if
c = EOF.
isalnum(c) c is in 0-9 or a-z or A-Z
isalpha(c) c is in A-Z or a-z
isascii(c) c is a 7 bit ascii character
iscntrl(c) c is a control character
isdigit(c) c is a decimal digit
islower(c) c is in a-z
isprint(c) c is a printing char
isgraph(c) c is a non-space printable character
ispunct(c) c is not alphanumeric
isspace(c) c is a space, tab or newline
isupper(c) c is in A-Z
isxdigit(c) c is in 0-9 or a-f or A-F
255
Example
#include <ctype.h>
#include <stdio.h>
void
main (void)
{
char buf[80];
int i;
gets(buf);
i = 0;
while(isalnum(buf[i]))
i++;
buf[i] = 0;
printf("’%s’ is the word\n", buf);
}
See Also
toupper(), tolower(), toascii()