std :: sort functor一行 [英] std::sort functor one line

问题描述

我已经声明了函子，并使用该函子作为参数进行了std :: sort调用.代码:

I have declared a functor and made a call so std::sort with that functor as a parameter. Code:

struct
{
    bool operator() (const CString& item1, const CString& item2){
        return MyClass::Compare( Order(_T("DESC")), item1, item2);
    }

}Comparer;

std::sort(AllObjects.GetData(), AllObjects.GetData() + AllObjects.GetSize(), Comparer);

一个简单的问题:我可以一行吗?

Simple question: can I do this in one line?

推荐答案

如果您的编译器支持

If your compiler supports c++11, you can use a lambda

std::sort(AllObjects.GetData(), AllObjects.GetData() + AllObjects.GetSize(),
          [](const CString& item1, const CString& item2) {
              return MyClass::Compare( Order(_T("DESC")), item1, item2);
          });

没有c ++ 11 ，您可以使用函数而不是函子来简化它

without c++11, you can simplify it only a little bit by using a function instead of a functor

static inline bool Comparer(const CString& item1, const CString& item2) {
    return MyClass::Compare(Order(_T("DESC")), item1, item2);
}

并将其用作最后一个参数.

and use that as the last parameter.

不幸的是(?)，只有一元或二进制函数对象的函数包装器.如果也有三元函数对象的包装器，则您可以进行类似于

Unfortunately (?), there are only function wrappers for unary or binary function objects. If there were wrappers for ternary function objects too, you could do something similar to

std::sort(AllObjects.GetData(), AllObjects.GetData() + AllObjects.GetSize(),
          std::bind1st(std::ptr_fun(MyClass::Compare), Order(_T("DESC"))));

如果您考虑使用 boost-绑定，您可以尝试使用

If you consider using boost - bind, you can try this instead

std::sort(AllObjects.GetData(), AllObjects.GetData() + AllObjects.GetSize(),
          boost::bind(MyClass::Compare, Order(_T("DESC")), _1, _2));

这等效于 std::bind "/questions/tagged/c％2b％2b11" class ="post-tag" title =显示已标记'c ++ 11'的问题"" rel ="tag"> c ++ 11 .

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