[C++/9.07] 괄호"()" 연산자 오버로딩과 함수 객체 Functor

#include<iostream>
using namespace std;

class Accumulator
{
private:
    int m_counter = 0;

public:
    int operator () (int i)
    {
        return (m_counter += i);
    }
};

int main()
{
    Accumulator acc;

        // functor
    cout << acc(10) << endl;
    cout << acc(20) << endl;

    return 0;
}