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Defined in header <functional> | ||
template<class Predicate> struct binary_negate | (until C++11) | |
template<class Predicate> struct binary_negate; | (since C++11) (deprecated in C++17) (removed in C++20) | |
std::binary_negate is a wrapper function object returning the complement of the binary predicate it holds.
The binary predicate type must define two member types,first_argument_type andsecond_argument_type, that are convertible to the predicate's parameter types. The function objects obtained fromstd::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, or from a call tostd::not2 have these types defined, as are function objects derived from the deprecatedstd::binary_function.
std::binary_negate objects are easily constructed with helper functionstd::not2.
Contents |
| Type | Definition |
first_argument_type | Predicate::first_argument_type |
second_argument_type | Predicate::second_argument_type |
result_type | bool |
(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) |
explicit binary_negate( Predicateconst& pred); | (until C++14) | |
constexprexplicit binary_negate( Predicateconst& pred); | (since C++14) | |
Constructs astd::binary_negate function object with the stored predicatepred.
| pred | - | predicate function object |
bool operator()( first_argument_typeconst& x, second_argument_typeconst& y)const; | (until C++14) | |
constexprbool operator()( first_argument_typeconst& x, second_argument_typeconst& y)const; | (since C++14) | |
Returns the logical complement of the result of callingpred(x, y).
| x | - | first argument to pass through to predicate |
| y | - | second argument to pass through to predicate |
The logical complement of the result of callingpred(x, y).
#include <algorithm>#include <cstddef>#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;for(int i=0; i<7;++i) v1.push_back(i); std::vector<int> v2(v1.size());std::reverse_copy(v1.begin(), v1.end(), v2.begin()); std::vector<bool> v3(v1.size()); std::binary_negate<same> not_same((same())); // C++11 solution:// 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(std::size_t i=0; i!= v1.size();++i)std::cout<< v1[i]<<" != "<< v2[i]<<" : "<< v3[i]<<'\n';}
Output:
0 != 6 : true1 != 5 : true2 != 4 : true3 != 3 : false4 != 2 : true5 != 1 : true6 != 0 : true
(deprecated in C++11)(removed in C++17) | adaptor-compatible binary function base class (class template)[edit] |
(C++11) | copyable wrapper of any copy constructible callable object (class template)[edit] |
(C++23) | move-only wrapper of any callable object that supports qualifiers in a given call signature (class template)[edit] |
(deprecated in C++17)(removed in C++20) | constructs customstd::binary_negate object (function template)[edit] |
(deprecated in C++11)(removed in C++17) | creates an adaptor-compatible function object wrapper from a pointer to function (function template)[edit] |
(deprecated in C++17)(removed in C++20) | wrapper function object returning the complement of the unary predicate it holds (class template)[edit] |
