std::unary_function

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C++
 
实用工具库
类型的支持 (basic types, RTTI, type traits)
动态内存管理
错误处理
程序实用工具
可变参数函数
日期和时间
函数对象
initializer_list（C++11）
bitset
hash（C++11）
关系运算符
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Relational operators
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rel_ops::operator!=
rel_ops::operator>
rel_ops::operator<=
rel_ops::operator>=
双和元组
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Pairs and tuples
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pair
tuple（C++11）
piecewise_construct_t（C++11）
piecewise_construct（C++11）
掉期，远期和移动
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Swap, forward and move
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swap
forward（C++11）
move（C++11）
move_if_noexcept（C++11）
declval（C++11）
 
函数对象
功能包装
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Function wrappers
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function（C++11）
mem_fn（C++11）
bad_function_call（C++11）
绑定
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Bind
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bind（C++11）
is_bind_expression（C++11）
is_placeholder（C++11）
_1, _2, _3, ...（C++11）
参考包装
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Reference wrappers
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reference_wrapper（C++11）
ref
cref		（C++11）
（C++11）
操作包装
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Operator wrappers
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否定词
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Negators
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已过时粘合剂和适配器
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Deprecated binders and adaptors
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unary_function（过时了）
binary_function（过时了）
ptr_fun（过时了）
pointer_to_unary_function（过时了）
pointer_to_binary_function（过时了）
mem_fun（过时了）
mem_fun_t
mem_fun1_t
const_mem_fun_t
const_mem_fun1_t		（过时了）
（过时了）
（过时了）
（过时了）
mem_fun_ref（过时了）
mem_fun_ref_t
mem_fun1_ref_t
const_mem_fun_ref_t
const_mem_fun1_ref_t		（过时了）
（过时了）
（过时了）
（过时了）
binder1st
binder2nd		（过时了）
（过时了）
bind1st
bind2nd		（过时了）
（过时了）
 
Defined in header <functional>
template <typename ArgumentType, typename ResultType>
struct unary_function;
 （过时了）
unary_function是创建一个参数的函数对象的基类.
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unary_function is a base class for creating function objects with one argument.
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unary_function不定义operator();预期派生类定义此。 unary_function只有两种类型 - argument_type和result_type - 模板参数的定义.
Original:
unary_function does not define operator(); it is expected that derived classes will define this. unary_function provides only two types - argument_type and result_type - defined by the template parameters.
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一些标准库函数对象适配器，如std::not1，要求他们适应有一定的定义的类型的函数对象;std::not1需要的函数对象，适应了一种名为argument_type。从unary_function接受一个参数的函数对象，推导是一个简单的方法，使他们与这些适配器兼容.
Original:
Some standard library function object adaptors, such as std::not1, require the function objects they adapt to have certain types defined; std::not1 requires the function object being adapted to have a type named argument_type. Deriving function objects that take one argument from unary_function is an easy way to make them compatible with those adaptors.
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unary_function被废弃，在C + +11。它的功能已经过时std::function.
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unary_function is deprecated in C++11. Its functionality has been made obsolete by std::function.
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[编辑] 会员类型

类型
Original:
Type
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 Definition
argument_type ArgumentType
result_type ResultType

[编辑] 为例

#include <algorithm>
#include <functional>
#include <iostream>
#include <vector>
 
struct less_than_7 : std::unary_function<int, bool>
{
    bool operator()(int i) const { return i < 7; }
};
 
int main()
{
    std::vector<int> v;
    for (int i = 0; i < 10; ++i) v.push_back(i);
 
    std::cout << std::count_if(v.begin(), v.end(), std::not1(less_than_7()));
 
    /* C++11 solution:
        // Cast to std::function<bool (int)> somehow - even with a lambda
        std::cout << std::count_if(v.begin(), v.end(),
            std::not1(std::function<bool (int)>([](int i){ return i < 7; }))
        );
    */
}

Output: 

3

[编辑] 另请参阅

（C++11）
包装任何类型的可调用对象与指定的函数调用签名
Original:
wraps callable object of any type with specified function call signature
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（类模板） [edit]
（过时了）
创建适配器兼容功能的包装对象从一个指针到函数
Original:
creates an adaptor-compatible function object wrapper from a pointer to function
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（函数模板） [edit]
（过时了）
适配器兼容的包装，一元函数的指针
Original:
adaptor-compatible wrapper for a pointer to unary function
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（类模板） [edit]
（过时了）
适配器兼容的二元函数的基类
Original:
adaptor-compatible binary function base class
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（类模板） [edit]
来自“http://zh.cppreference.com/mwiki/index.php?title=cpp/utility/functional/unary_function&oldid=26548”