C++框架如何通过使用设计模式提高可维护性和可扩展性？

class Context {

public:

    Context(std::unique_ptr<Strategy> strategy) : strategy(std::move(strategy)) {}

    void execute() {

        strategy->execute();

    }

private:

    std::unique_ptr<Strategy> strategy;

};

class Strategy {

public:

    virtual void execute() = 0;

};

class ConcreteStrategyA : public Strategy {

public:

    void execute() override {

        // Implement behavior for strategy a

    }

};

class ConcreteStrategyB : public Strategy {

public:

    void execute() override {

        // Implement behavior for strategy b

    }

};

int main() {

    Context context(std::make_unique<ConcreteStrategyA>());

    context.execute();

    context.strategy = std::make_unique<ConcreteStrategyB>();

    context.execute();

    return 0;

}