Defined in header <ctype.h> int isdigit( int ch ); Checks if the given character is a numeric character (0123456789). The behavior is undefined if the value of ch is not representable as unsigned char and is
Like all other functions from <cctype>, the behavior of std::isdigit is undefined if the argument's value is neither representable as unsigned char nor equal to EOF. To use these functions safely with plain chars (or signed chars), the argument should first be converted to unsigned char: ...
std::isdigit 和std::isxdigit 是仅有的不受当前安装的 C 本地环境影响的标准窄字符分类函数。尽管某些实现(例如 Microsoft 在 1252 代码页)可能分类另外的单字节字符为数字。 同所有其他来自 <cctype> 的函数,若实参值既不能表示为 unsigned char 又不等于 EOF 则std::isxdigit 的行为未定义。为了以单纯的 ...
isdigit(std::locale) Verifica se un carattere è classificato come una cifra da un locale Original: checks if a character is classified as a digit by a locale The text has been machine-translated viaGoogle Translate. You can help to correct and verify the translation. Clickherefor instructions...
isdigit iswdigit isxdigit iswxdigit decimal hexadecimal octal 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)...
isdigit digit from 0 through 9. islower lowercase letter. isprint printable character (including a space). ispunct printable character other than a digit, letter, or space. isupper uppercase letter. Otherwise, it returns 0. isspace whitespace character. (' ', ' \n ', ' \v ', ' \t ')...
isdigit 与isxdigit 是仅有的不受当前安装的 C 本地环境影响的标准窄字符分类函数,尽管一些实现(例如 Microsoft 于 1252 代码页)可能将额外的单字节字符分类为数字。 示例运行此代码 #include <stdio.h> #include <ctype.h> #include <limits.h> int main(void) { for (int ndx=0; ndx<=UCHAR_MAX; ndx...
isdigit 和isxdigit 是仅有的不受当前安装的 C 本地环境影响的标准窄字符分类函数。尽管某些实现(例如 Microsoft 在 1252 代码页)可能分类另外的单字节字符为数字。 示例运行此代码 #include <stdio.h> #include <ctype.h> #include <limits.h> int main(void) { for (int ndx=0; ndx<=UCHAR_MAX; ndx++...
此标头是空终结字节字符串库的一部分。 Functions isalnum 检查字符是否是字母或数字 (函数) isalpha 检查字符是否是字母 (函数) islower 检查字符是否是小写字母 (函数) isupper 检查字符是否是大写字母 (函数) isdigit 检查字符是否是数字 (函数) isxdigit 检查字符是否是十六进制字符 (函数) iscntrl ...
ASCII 值 字符 iscntrl iswcntrl isprint iswprint isspace iswspace isblank iswblank isgraph iswgraph ispunct iswpunct isalnum iswalnum isalpha iswalpha isupper iswupper islower iswlower isdigit iswdigit isxdigit iswxdigit 十进制 十六进制 八进制 0–8 \x0–\x8 \0–\10 控制码 (...