23种设计模式C++实例之策略模式

#include <iostream>

using namespace std;
/*
 * 策略模式
 * 策略模式定义了一系列的算法，并将每一个算法封装起来，而且使它们还可以相互替换。
 * 策略模式让算法独立于使用它的客户而独立变化。
 * */
class Strategy {
public:
virtual ~Strategy() {}
virtual void crypt() = 0;
};

class AES: public Strategy {
public:
virtual void crypt() {
cout << "AES crypt" << endl;
        }
};

class DES: public Strategy {
public:
virtual void crypt() {
cout << "DES crypt" << endl;
        }
};

class Context {
public:
void setStrategy(Strategy* strategy) {
            m_strategy = strategy;
        }

void operate() {
            m_strategy->crypt();
        }
private:
        Strategy* m_strategy;
};

int main() {
    Strategy* des = new DES;
    des->crypt();

cout << endl;

    Context* context = new Context;
    context->setStrategy(des);
    context->operate();

delete context;
delete des;

return 0;
}