class Arg1,
class Arg2,
class Result
std::binary_function is a base class for creating function objects with two arguments.
std::binary_function does not define operator(); it is expected that derived classes will define this. std::binary_function provides only three types - first_argument_type, second_argument_type and result_type - defined by the template parameters.
Some standard library function object adaptors, such as std::not2, require the function objects they adapt to have certain types defined; std::not2 requires the function object being adapted to have two types named first_argument_type and second_argument_type. Deriving function objects that take two arguments from std::binary_function is an easy way to make them compatible with those adaptors.
std::binary_function is deprecated in C++11 and removed in C++17.
first_argument_type Arg1 second_argument_type Arg2 result_type Result [edit] Example
#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<char> v1{'A', 'B', 'C', 'D', 'E'};
std::vector<char> v2{'E', 'D', 'C', 'B', 'A'};
std::vector<bool> v3(v1.size());
std::transform(v1.begin(), v1.end(), v2.begin(), v3.begin(), std::not2(same()));
std::cout << std::boolalpha;
for (std::size_t i = 0; i < v1.size(); ++i)
std::cout << v1[i] << " != " << v2[i] << " : " << v3[i] << '\n';
}
Output:
A != E : true B != D : true C != C : false D != B : true E != A : true[edit] See also copyable wrapper of any copy constructible callable object
(deprecated in C++11)(removed in C++17)
creates an adaptor-compatible function object wrapper from a pointer to function(deprecated in C++11)(removed in C++17)
adaptor-compatible wrapper for a pointer to binary function(deprecated in C++11)(removed in C++17)
adaptor-compatible unary function base classRetroSearch is an open source project built by @garambo | Open a GitHub Issue
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