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#include <iostream>
using namespace std;

class FlyBehaviorInterface {
public:
    virtual void fly() = 0;
    virtual ~FlyBehaviorInterface() = default;
};

class FlyWithWings : public FlyBehaviorInterface {
public:
    void fly() override {
        cout << "Flying with wings!" << endl;
    }
};

class FlyNoWay : public FlyBehaviorInterface {
public:
    void fly() override {
        cout << "I can't fly!" << endl;
    }
};

class Duck {
public:
    FlyBehaviorInterface* flyBehavior;

    Duck(FlyBehaviorInterface* fb) {
        this->flyBehavior = fb;
    }

    void performFly() {
        flyBehavior->fly();
    }
};

int main() {
    FlyBehaviorInterface* flyWithWings = new FlyWithWings();
    Duck* mallardDuck = new Duck(flyWithWings);
    mallardDuck->performFly(); // Flying with wings!

    FlyBehaviorInterface* flyNoWay = new FlyNoWay();
    Duck* rubberDuck = new Duck(flyNoWay);
    rubberDuck->performFly(); // I can't fly!

    delete flyWithWings;
    delete mallardDuck;
    delete flyNoWay;
    delete rubberDuck;

    return 0;
}