策略模式

策略模式：它定义了算法家族，分别封装起来，让他们之间可以互相替换，此模式让算法变化，不会影响到使用算法的客户。

#include <iostream>
using namespace std;
class Strategy
{
public:
    virtual void algorithm(){};
};

class StrategyA:public Strategy
{
public:

    void algorithm()
    {
        printf("a");
    }
};

class StrategyB:public Strategy
{
public:
    void algorithm()
    {
        printf("b");
    }
};

class Context
{
    Strategy* strategy;
public:
    Context(Strategy* strategy)
    {
        this->strategy=strategy;
    }
    void algorithm()
    {
        strategy->algorithm();
    }
};


int main(int argc, const char * argv[])
{
    Context* context=new Context(new StrategyA());
    context->algorithm();
    Context* context2=new Context(new StrategyB());
    context2->algorithm();

}