| Defined in header <locale> | ||
|---|---|---|
template< class charT > bool isdigit( charT ch, const locale& loc ); |
Checks if the given character is classified as a digit by the given locale's std::ctype facet.
Parameters
| ch | - | character |
| loc | - | locale |
Return value
Returns true if the character is classified as a digit, false otherwise.
Possible implementation
template< class charT >
bool isdigit( charT ch, const std::locale& loc ) {
return std::use_facet<std::ctype<charT>>(loc).is(std::ctype_base::digit, ch);
} |
Example
#include <iostream>
#include <locale>
#include <string>
#include <set>
struct jdigit_ctype : std::ctype<wchar_t>
{
std::set<wchar_t> jdigits{L'一',L'二',L'三',L'四',L'五',L'六',L'七',L'八',L'九',L'十'};
bool do_is(mask m, char_type c) const {
if ((m & digit) && jdigits.count(c))
return true; // Japanese digits will be classified as digits
return ctype::do_is(m, c); // leave the rest to the parent class
}
};
int main()
{
std::wstring text = L"123一二三１２３";
std::locale loc(std::locale(""), new jdigit_ctype);
std::locale::global(std::locale(""));
std::wcout.imbue(std::locale());
for(wchar_t c : text)
if(std::isdigit(c, loc))
std::wcout << c << " is a digit\n";
else
std::wcout << c << " is NOT a digit\n";
}Output:
1 is a digit 2 is a digit 3 is a digit 一 is a digit 二 is a digit 三 is a digit １ is NOT a digit ２ is NOT a digit ３ is NOT a digit
See also
| checks if a character is a digit (function) | |
| checks if a wide character is a digit (function) |
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