std::isalpha

From Cppreference

C++ Standard Library
Language Utilities library Strings library Containers library Algorithms library Iterators library Numerics library Input/output library Localizations library Regular expressions library (C++11) Atomic operations library (C++11) Thread support library (C++11)
Strings library
Narrow character strings Wide character strings Classes basic_string char_traits
Narrow null-terminated strings
Functions Character manipulation isalnum isalpha islower isupper isdigit isxdigit isblank (C++11) iscntrl isgraph isspace isprint ispunct tolower toupper Conversions to numeric formats atof atoi strtol strtoul strtof String manipulation strcpy strncpy strcat strncat strxfrm String examination strlen strcmp strncmp strcoll strchr strrchr strspn strcspn strpbrk strstr strtok Memory manipulation memchr memcmp memset memcpy memmove Miscellaneous strerror

Defined in header <cctype>
int isalpha( int ch );

Checks if the given character is an alphabetic character, i.e. either an uppercase letter (ABCDEFGHIJKLMNOPQRSTUVWXYZ), or a lowercase letter (abcdefghijklmnopqrstuvwxyz).

[edit] Parameters

ch

-

character

[edit] Return value

non-zero value (true) if the character is an alphabetic character, 0 (false) otherwise.

[edit] See also

isalpha(std::locale)	checks if a character is classified as alphabetic by a locale (function template)
iswalpha	checks if a wide character is alphabetic (function)

ASCII values (hex)		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	0x00-0x08	control codes (NUL, etc.)	≠0	0	0	0	0	0	0	0	0	0	0	0
9	0x09-0x0D	tab (\t)	≠0	0	≠0	≠0	0	0	0	0	0	0	0	0
10 - 13	0x09-0x0D	whitespace (\f,\v,\n,\r)	≠0	0	≠0	0	0	0	0	0	0	0	0	0
14 - 31	0x0E-0x1F	control codes	≠0	0	0	0	0	0	0	0	0	0	0	0
32	0x20	space	0	≠0	≠0	≠0	0	0	0	0	0	0	0	0
33 - 47	0x21-0x2F	!"#$%&'()*+,-./	0	≠0	0	0	≠0	≠0	0	0	0	0	0	0
48 - 57	0x30-0x39	01234567890	0	≠0	0	0	≠0	0	≠0	0	0	0	≠0	≠0
58 - 64	0x3a-0x40	:;<=>?@	0	≠0	0	0	≠0	≠0	0	0	0	0	0	0
65 - 70	0x41-0x46	ABCDEF	0	≠0	0	0	≠0	0	≠0	≠0	≠0	0	0	≠0
71 - 90	0x47-0x5A	GHIJKLMNOPQRSTUVWXYZ	0	≠0	0	0	≠0	0	≠0	≠0	≠0	0	0	0
91 - 96	0x5B-0x60	[\]^_`	0	≠0	0	0	≠0	≠0	0	0	0	0	0	0
97 -102	0x61-0x66	abcdef	0	≠0	0	0	≠0	0	≠0	≠0	0	≠0	0	≠0
103-122	0x67-0x7A	ghijklmnopqrstuvwxyz	0	≠0	0	0	≠0	0	≠0	≠0	0	≠0	0	0
123-126	0x7B-0x7E	{|}~	0	≠0	0	0	≠0	≠0	0	0	0	0	0	0
127	0x7F	backspace character (DEL)	≠0	0	0	0	0	0	0	0	0	0	0	0