iscsymf -- Test for Valid C Identifier Initial Symbol

SYNOPSIS
#include <lctype.h>
int iscsymf(int c);
DESCRIPTION
iscsymf
tests an integer value to determine whether it is a
character that can appear as the first character of a C identifier.
For this implementation, the uppercase and lowercase alphabetic
characters and the underscore are included.
RETURN VALUE
iscsymf
returns 0 if the character is not a valid first character
in a C identifier, or a nonzero value if it is. If the argument is
EOF
, 0 is returned.
CAUTION
The effect of iscsymf
on a noncharacter argument other than EOF
is undefined. Do not assume that iscsymf
returns either 0 or 1.
EXAMPLE
#include <lctype.h>
#include <stdio.h>
#define IDMAX 40
main()
{
char id[IDMAX+1];
int i;
char *text;
char input[IDMAX];
puts("Enter any identifier (no more than 40 characters long).");
text = gets(input);
/* Copy a C identifier from text to id. */
if (iscsymf(text[0])) {
id[0] = text[0];
for (i = 1; i < IDMAX && iscsym(text[i]); ++i)
id[i] = text[i];
id[i] = '0';
printf("The identifier is copied as %sn", id);
}
else
puts("The first character of identifier is not acceptable.);
}
RELATED FUNCTIONS
iscsym
SEE ALSO