#include <iostream>

using namespace std;

class Strategy {

public:

virtual void Interface() = 0;

virtual ~Strategy() { }

};

class ConcreteStrategyA :public Strategy {

public:

void Interface() {

cout << "ConcreteStrategyA::Interface..." << endl;

}

};

class ConcreteStrategyB :public Strategy {

public:

void Interface() {

cout << "ConcreteStrategyB::Interface..." << endl;

}

};

class Context {

public:

Context(Strategy *stg) {

_stg = stg;

}

void DoAction() {

_stg->Interface();

}

private:

Strategy *_stg;

};

int main() {

Strategy *ps = new ConcreteStrategyA();

Context *pc = new Context(ps);

pc->DoAction();

delete pc;

delete ps;

return 0;

}