std::iscntrl
STD：：iscntrl
| Defined in header | | |
|---|---|---|
| int iscntrl( int ch | | |
检查给定字符是否为按当前安装的C语言环境分类的控制字符。在默认情况下，“C”区域设置中，控制字符是带有代码的字符。0x00-0x1F和0x7F...
如果ch不能表示为unsigned char不等于EOF...
参数
| ch | - | character to classify |
|---|
返回值
如果字符是控制字符，则为非零值，否则为零。
例
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#include <iostream>
#include <cctype>
#include <clocale>
int main()
{
unsigned char c = '\x94'; // the control code CCH in ISO-8859-1
std::cout << "iscntrl(\'\\x94\', default C locale) returned "
<< std::boolalpha << (bool)std::iscntrl(c) << '\n';
std::setlocale(LC_ALL, "en_GB.iso88591"
std::cout << "iscntrl(\'\\x94\', ISO-8859-1 locale) returned "
<< std::boolalpha << (bool)std::iscntrl(c) << '\n';
}
二次
产出：
二次
iscntrl('\x94', default C locale) returned false
iscntrl('\x94', ISO-8859-1 locale) returned true
二次
另见
| iscntrl(std::locale) | checks if a character is classified as a control character by a locale (function template) |
|---|---|
| iswcntrl | checks if a wide character is a control character (function) |
c iscntrl文件
| 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 |
| 9 | 0x09 | tab (\t) | ≠0 | 0 | ≠0 | ≠0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 10 - 13 | 0x0A-0x0D | whitespaces (\n,\v,\f,\r) | ≠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 |
| 32 | 0x20 | space | 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 |
| 48 - 57 | 0x30-0x39 | 0123456789 | 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 |
| 65 - 70 | 0x41-0x46 | ABCDEF | 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 |
| 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 |
| 103-122 | 0x67-0x7A | ghijklmnopqrstuvwxyz | 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 |
| 127 | 0x7F | backspace character (DEL) | ≠0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
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