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isxdigit |
Portability: | ISO/ANSI C conforming |
SYNOPSIS | |
DESCRIPTION | |
RETURN VALUE | |
CAUTION | |
EXAMPLE | |
RELATED FUNCTIONS | |
SEE ALSO |
SYNOPSIS |
#include <ctype.h> int isxdigit(int c);
DESCRIPTION |
isxdigit
tests an integer value
c
to determine whether
it is a hexadecimal digit (uppercase or lowercase).
RETURN VALUE |
isxdigit
returns 0 if the character is not a hexadecimal digit, or a nonzero value
if it is. If the argument is
EOF
, 0 is
returned.
CAUTION |
The effect of
isxdigit
on a noncharacter argument other than
EOF
is undefined. Do not assume that
isxdigit
returns either 0 or 1.
EXAMPLE |
#include <ctype.h> #include <stdio.h> #define IDLEN 40 main() { char line[IDLEN]; char id[IDLEN+1]; char *text; int i; puts("Enter a string consisting of hexadecimal characters: "); text = gets(line); /* Copy from text to id. */ for (i = 0; i < IDLEN ; ++i) { if (isxdigit(text[i])) id[i] = text[i]; else id[i] = '*'; } id[i] = '\0'; /* All nonhex characters have been replaced by '*'. */ puts("You have entered the following hexadecimal characters:"); printf("%s\n", id); }
RELATED FUNCTIONS |
SEE ALSO |
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