std::collate
STD：校对
| Defined in header | | |
|---|---|---|
| template< class CharT > class collate; | | |
类std::collate封装特定于地区的排序规则%28比较%29和字符串散列.。此面由std::basic_regex并且可以通过std::locale::operator()，直接指向所有期望字符串比较谓词的标准算法。
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继承图
标准库提供了两个独立的%28区域设置无关%29的专门化：
在标头中定义<locale>
*。
STD：校对<char>实现字节字符串的字典排序
STD：：整理<wchar[医]实现宽字符串的字典排序
此外，在C++程序中构造的每个locale对象都实现了自己的%28 locale特定于这些专门化的%29版本。
成员类型
| Member type | Definition |
|---|---|
| char_type | CharT |
| string_type | std::basic_string<CharT> |
成员函数
| (constructor) | constructs a new collate facet (public member function) |
|---|---|
| (destructor) | destructs a collate facet (protected member function) |
| compare | invokes do_compare (public member function) |
| transform | invokes do_transform (public member function) |
| hash | invokes do_hash (public member function) |
成员对象
| static std::locale::id id | id of the locale (public member object) |
|---|
受保护成员函数
| do_compare virtual | compares two strings using this facet's collation rules (virtual protected member function) |
|---|---|
| do_transform virtual | transforms a string so that collation can be replaced by comparison (virtual protected member function) |
| do_hash virtual | generates an integer hash value using this facet's collation rules (virtual protected member function) |
例
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#include <locale>
#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
int main()
{
std::wcout.imbue(std::locale("")
std::vector<std::wstring> v = {L"ar", L"zebra", L"\u00f6grupp", L"Zebra", L"\u00e4ngel",
L"\u00e5r", L"f\u00f6rnamn"};
std::wcout << "Default locale collation order: ";
std::sort(v.begin(), v.end()
for (auto s : v) std::wcout << s << ' '; std::wcout << '\n';
std::wcout << "English locale collation order: ";
std::sort(v.begin(), v.end(), std::locale("en_US.UTF-8")
for (auto s : v) std::wcout << s << ' '; std::wcout << '\n';
std::wcout << "Swedish locale collation order: ";
std::sort(v.begin(), v.end(), std::locale("sv_SE.UTF-8")
for (auto s : v) std::wcout << s << ' '; std::wcout << '\n';
}
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产出：
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Default locale collation order: Zebra ar förnamn zebra ängel år ögrupp
English locale collation order: ängel ar år förnamn ögrupp zebra Zebra
Swedish locale collation order: ar förnamn zebra Zebra år ängel ögrupp
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另见
| operator() | lexicographically compares two strings using this locale's collate facet (public member function of std::locale) |
|---|---|
| collate_byname | creates a collate facet for the named locale (class template) |
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