an example of functors in cpp

Functors.cpp

#include <iostream>

using namespace std;

class myIncreasingFunctor {

    int increaseBy;
    public:
    myIncreasingFunctor(int _value) {
        increaseBy = _value;
    }

    int operator () (int _value) {
        return  _value + increaseBy;
    }

};

int main()
{

    myIncreasingFunctor IncreaseBy5(5);
    cout << IncreaseBy5(10); // output 15
    cout << IncreaseBy5(20); // output 25;
    myIncreasingFunctor IncreaseBy10(10);
    cout << IncreaseBy10(10); // output 20
    cout << IncreaseBy10(20); // output 30;
}