isxdigit - cppreference.com (2024)

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Program utilities
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Error handling
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Strings library
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Technical Specifications
Symbol index

[edit]

Strings library

Byte strings
Multibyte strings
Wide strings

[edit]

Null-terminated byte strings

Functions

Character manipulation

isalnum
isalpha
islower
isupper
isdigit
isxdigit
isblank (C99)

iscntrl
isgraph
isspace
isprint
ispunct
tolower
toupper

Conversions to and from numeric formats

atoiatolatoll (C99)
atof
strtolstrtoll (C99)
strtoulstrtoull (C99)

strtoimaxstrtoumax (C99)(C99)
strtofstrtodstrtold (C99)(C99)
strfromfstrfromdstrfroml (C23)(C23)(C23)

String manipulation

strcpystrcpy_s (C11)
strncpystrncpy_s (C11)
strcatstrcat_s (C11)

strncatstrncat_s (C11)
strxfrm
strdup (C23)
strndup (C23)

String examination

strlenstrnlen_s (C11)
strcmp
strncmp
strcoll
strchr
strrchr

strspn
strcspn
strpbrk
strstr
strtokstrtok_s (C11)

Memory manipulation

memchr
memcmp
memsetmemset_explicitmemset_s (C23)(C11)

memcpymemcpy_s (C11)
memmovememmove_s (C11)
memccpy (C23)

Miscellaneous

strerrorstrerror_sstrerrorlen_s

(C11)(C11)

[edit] Parameters

character to classify

[edit] Return value

Non-zero value if the character is an hexadecimal numeric character, zero otherwise.

[edit] Notes

isdigit and isxdigit are the only standard narrow character classification functions that are not affected by the currently installed C locale, although some implementations (e.g. Microsoft in 1252 codepage) may classify additional single-byte characters as digits.

[edit] Example

Run this code

#include <ctype.h>#include <limits.h>#include <stdio.h>int main(void){ for (int ndx = 0; UCHAR_MAX >= ndx; ++ndx) if (isxdigit(ndx)) printf("%c", ndx); printf("\n");}

Output:

0123456789ABCDEFabcdef

[edit] References

C17 standard (ISO/IEC 9899:2018):

7.4.1.12 The isxdigit function (p: 147)

C11 standard (ISO/IEC 9899:2011):

7.4.1.12 The isxdigit function (p: 203)

C99 standard (ISO/IEC 9899:1999):

7.4.1.12 The isxdigit function (p: 184)

C89/C90 standard (ISO/IEC 9899:1990):

4.3.1.11 The isxdigit function

[edit] See also

iswxdigit (C95)	checks if a wide character is a hexadecimal character (function) [edit]
C++ documentation for isxdigit

ASCII values			characters	`iscntrl` `iswcntrl`	`isprint` `iswprint`	`isspace` `iswspace`	`isblank` `iswblank`	`isgraph` `iswgraph`	`ispunct` `iswpunct`	`isalnum` `iswalnum`	`isalpha` `iswalpha`	`isupper` `iswupper`	`islower` `iswlower`	`isdigit` `iswdigit`	`isxdigit` `iswxdigit`
decimal	hexadecimal	octal	characters	`iscntrl` `iswcntrl`	`isprint` `iswprint`	`isspace` `iswspace`	`isblank` `iswblank`	`isgraph` `iswgraph`	`ispunct` `iswpunct`	`isalnum` `iswalnum`	`isalpha` `iswalpha`	`isupper` `iswupper`	`islower` `iswlower`	`isdigit` `iswdigit`	`isxdigit` `iswxdigit`
0–8	`\x0`–`\x8`	`\0`–`\10`	control codes (`NUL`, etc.)	`≠0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`
9	`\x9`	`\11`	tab (`\t`)	`≠0`	`0`	`≠0`	`≠0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`
10–13	`\xA`–`\xD`	`\12`–`\15`	whitespaces (`\n`, `\v`, `\f`, `\r`)	`≠0`	`0`	`≠0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`
14–31	`\xE`–`\x1F`	`\16`–`\37`	control codes	`≠0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`
32	`\x20`	`\40`	space	`0`	`≠0`	`≠0`	`≠0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`
33–47	`\x21`–`\x2F`	`\41`–`\57`	`!"#$%&'()*+,-./`	`0`	`≠0`	`0`	`0`	`≠0`	`≠0`	`0`	`0`	`0`	`0`	`0`	`0`
48–57	`\x30`–`\x39`	`\60`–`\71`	`0123456789`	`0`	`≠0`	`0`	`0`	`≠0`	`0`	`≠0`	`0`	`0`	`0`	`≠0`	`≠0`
58–64	`\x3A`–`\x40`	`\72`–`\100`	`:;<=>?@`	`0`	`≠0`	`0`	`0`	`≠0`	`≠0`	`0`	`0`	`0`	`0`	`0`	`0`
65–70	`\x41`–`\x46`	`\101`–`\106`	`ABCDEF`	`0`	`≠0`	`0`	`0`	`≠0`	`0`	`≠0`	`≠0`	`≠0`	`0`	`0`	`≠0`
71–90	`\x47`–`\x5A`	`\107`–`\132`	`GHIJKLMNOP` `QRSTUVWXYZ`	`0`	`≠0`	`0`	`0`	`≠0`	`0`	`≠0`	`≠0`	`≠0`	`0`	`0`	`0`
91–96	`\x5B`–`\x60`	`\133`–`\140`	[\]^_`	`0`	`≠0`	`0`	`0`	`≠0`	`≠0`	`0`	`0`	`0`	`0`	`0`	`0`
97–102	`\x61`–`\x66`	`\141`–`\146`	`abcdef`	`0`	`≠0`	`0`	`0`	`≠0`	`0`	`≠0`	`≠0`	`0`	`≠0`	`0`	`≠0`
103–122	`\x67`–`\x7A`	`\147`–`\172`	`ghijklmnop` `qrstuvwxyz`	`0`	`≠0`	`0`	`0`	`≠0`	`0`	`≠0`	`≠0`	`0`	`≠0`	`0`	`0`
123–126	`\x7B`–`\x7E`	`\172`–`\176`	`{\|}~`	`0`	`≠0`	`0`	`0`	`≠0`	`≠0`	`0`	`0`	`0`	`0`	`0`	`0`
127	`\x7F`	`\177`	backspace character (`DEL`)	`≠0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`

Defined in header `<ctype.h>`
int isxdigit( int ch );