[C++] bind_front

개요

• 인자로 전달된 함수에 대한 전달 호출 래퍼를 생성하는 함수
• bind_front
  • C++20
  • 함수의 첫번째 매개변수부터 바인드

예제

• 코드

   #include <functional>
   #include <iostream>
      
   using namespace std;
      
   int main() {
   	auto test1 = []() {
   		auto plus = [](int x, int y, int z) { return x + y + z; };
      
   		auto bind1 = bind_front(plus, 1);
   		cout << bind1(2, 3) << endl;
      
   		auto bind2 = bind_front(plus, 1, 2);
   		cout << bind2(3) << endl;
      
   		auto bind3 = bind_front(plus, 1, 2, 3);
   		cout << bind3() << endl;
   	};
   	test1();
      
   	cout << endl << "------" << endl << endl;
      
   	auto test2 = []() {
   		class Test {
   			private:
   				int i;
      
   			public:
   				Test(int i) : i(i) {}
   				int plus(int value) { return this->i + value; }
      
   				void SetI(int i) { this->i = i; };
   		};
      
   		auto bind1 = bind_front(mem_fn(&Test::plus), Test(1));
   		cout << bind1(10) << endl;
      
   		cout << "~~~~~~" << endl;
      
   		Test t1(1);
   		auto bind2 = bind_front(mem_fn(&Test::plus), t1);
   		cout << bind2(10) << endl;
   		t1.SetI(-1);
   		cout << bind2(10) << endl;
      
   		cout << "~~~~~~" << endl;
      
   		Test t2(1);
   		auto bind3 = bind_front(mem_fn(&Test::plus), &t2);
   		cout << bind3(10) << endl;
   		t2.SetI(-1);
   		cout << bind3(10) << endl;
   	};
   	test2();
      
   	return 0;
   }
  

• 실행 결과

   6
   6
   6
      
   ------
      
   11
   ~~~~~~
   11
   11
   ~~~~~~
   11
   9