#include <vector>
#include <iostream>

using namespace std;

class Behaviour
{
public:
    Behaviour() = default;
    virtual ~Behaviour() = default;

    virtual int apply(int other) = 0;
private:
};

class Add : public Behaviour
{
public:
    Add(int value) : value{value} {}
    virtual int apply(int other) override {
	return other += value;
    }
    
private:
    int value;
};

class Factorial : public Behaviour
{
public:
    Factorial() {};

    virtual int apply(int other) override {
	int iterations{other};
	int sum{1};
	for ( int i{1}; i <= iterations; ++i ) {
	    sum *= i;
	}
	return sum;
    }
    
private:
};

int main()
{   
    int value{0};
    Add a1{3};
    Factorial f1{};
    Add a2{1};
    Factorial f2{};
    std::vector<Behaviour*> behaviours { &a1, &f1, &a2, &f2 };
    
    for ( Behaviour* behaviour_pointer : behaviours ) {
	value = (*behaviour_pointer).apply(value);
    }
    std::cout << value << std::endl;

}