isxdigit

isxdigit

Hexadecimal Digit Test

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      /* All nonhex characters have been replaced by '*'.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

isdigit

SEE ALSO

Character Type Macros and Functions

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