std::binary_negate
Defined in header <functional> | | |
|---|---|---|
template< class Predicate > struct binary_negate : public std::binary_function< Predicate::first_argument_type, Predicate::second_argument_type, bool >; | | (until C++11) |
template< class Predicate > struct binary_negate; | | (since C++11) (deprecated in C++17) |
binary_negate是一个包装函数对象，返回它所持有的二进制谓词的补码。
二进制谓词类型必须定义两个成员类型，first_argument_type和second_argument_type可转换为谓词%27s参数类型的。从std::owner_less，，，std::ref，，，std::cref，，，std::plus，，，std::minus，，，std::multiplies，，，std::divides，，，std::modulus，，，std::equal_to，，，std::not_equal_to，，，std::greater，，，std::less，，，std::greater_equal，，，std::less_equal，，，std::logical_not，，，std::logical_or，，，std::bit_and，，，std::bit_or，，，std::bit_xor，，，std::mem_fn，，，std::map::value_comp，，，std::multimap::value_comp，，，std::function，或者从电话到std::not2定义这些类型，就像从已弃用的函数对象派生的函数对象一样。std::binary_function...
binary_negate对象很容易用助手函数构造。std::not2...
成员类型
Type | Definition |
|---|---|
first_argument_type | Predicate::first_argument_type |
second_argument_type | Predicate::second_argument_type |
result_type | bool |
成员函数
(constructor) | constructs a new binary_negate object with the supplied predicate (public member function) |
|---|---|
operator() | returns the logical complement of the result of a call to the stored predicate (public member function) |
STD：二进制[医]否定：：二进制[医]否定
explicit binary_negate( Predicate const& pred ); | | (until C++14) |
|---|---|---|
explicit constexpr binary_negate( Predicate const& pred ); | | (since C++14) |
构造一个binary_negate具有存储谓词的函数对象。pred...
参数
pred | - | predicate function object |
|---|
STD：二进制[医]否定：：操作员%28%29
bool operator()( first_argument_type const& x, second_argument_type const& y ) const; | | (until C++14) |
|---|---|---|
constexpr bool operator()( first_argument_type const& x, second_argument_type const& y ) const; | | (since C++14) |
返回调用结果的逻辑补码。pred(x, y)...
参数
x | - | first argument to pass through to predicate |
|---|---|---|
y | - | second argument to pass through to predicate |
返回值
调用结果的逻辑补充pred(x, y)...
例
二次
#include <algorithm>
#include <functional>
#include <iostream>
#include <vector>
struct same : std::binary_function<int, int, bool>
{
bool operator()(int a, int b) const { return a == b; }
};
int main()
{
std::vector<int> v1;
std::vector<int> v2;
for (int i = 0; i < 10; ++i) v1.push_back(i);
for (int i = 0; i < 10; ++i) v2.push_back(10 - i);
std::vector<bool> v3(v1.size());
std::binary_negate<same> not_same((same()));
std::transform(v1.begin(), v1.end(), v2.begin(), v3.begin(), not_same);
/* C++11 solution:
// Use std::function<bool (int, int)>
std::function<bool (int, int)> not_same =
[](int x, int y)->bool{ return !same()(x, y); };
std::transform(v1.begin(), v1.end(), v2.begin(), v3.begin(), not_same);
*/
std::cout.setf(std::ios_base::boolalpha);
for (int i = 0; i < 10; ++i)
std::cout << v1[i] << ' ' << v2[i] << ' ' << v3[i] << '\n';
}二次
产出：
二次
0 10 true
1 9 true
2 8 true
3 7 true
4 6 true
5 5 false
6 4 true
7 3 true
8 2 true
9 1 true二次
另见
binary_function (until C++17) | adaptor-compatible binary function base class (class template) |
|---|---|
function (C++11) | wraps callable object of any type with specified function call signature (class template) |
not2 (deprecated) | constructs custom std::binary_negate object (function template) |
ptr_fun (until C++17) | creates an adaptor-compatible function object wrapper from a pointer to function (function template) |
unary_negate (deprecated) | wrapper function object returning the complement of the unary predicate it holds (class template) |
© cppreference.com在CreativeCommonsAttribution下授权-ShareAlike未移植许可v3.0。
本文档系腾讯云开发者社区成员共同维护，如有问题请联系 cloudcommunity@tencent.com
