策略模式

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简介

UML类图

代码示例

#include <iostream>
using namespace std;

class Strategy
{
public:
  virtual void Algorithm() = 0;
};

class StrategyA : public Strategy
{
public:
  virtual void Algorithm() {
    std::cout << "StrategyA" << std::endl;
  }
};

class StrategyB : public Strategy
{
public:
  virtual void Algorithm() {
    std::cout << "StrategyB" << std::endl;
  }
};

class Context
{
public:
  Context(Strategy *pStrategy) {
    m_pStrategy = pStrategy;
  }
  ~Context() { };

  void Operation() {
    if (m_pStrategy != NULL) {
        m_pStrategy->Algorithm();
    }
  }

private:
  Strategy *m_pStrategy;
};

int main(int argc , char **argv)
{
  Context* pContext = new Context(new StrategyA());
  pContext->Operation();
  delete pContext;

  pContext = new Context(new StrategyB());
  pContext->Operation();

  return 0;
}