1 #include <iostream> 2 #include <string> 3 using namespace std; 4  5 class Work; 6 class State; 7 class ForenonnState; 8  9 10 class State11 {12 public:13     virtual void writeProgram(Work*) = 0;14 };15 16 class Work17 {18 public:19     int hour;20     State *current;21     Work();22     void writeProgram()23     {24         current->writeProgram(this);25     }26 };27 28 class EveningState : public State29 {30 public:31     void writeProgram(Work *w)32     {33         cout << "当前时间: " << w->hour << "心情很好，在看《明朝那些事儿》，收获很大！" << endl;34     }35 };36 37 class AfternoonState : public State38 {39 public:40     void writeProgram(Work *w)41     {42         if (w->hour < 19)43         {44             cout << "当前时间: " << w->hour << "下午午睡后，工作还是精神百倍!" << endl;45         }46         else47         {48             w->current = new EveningState();49             w->writeProgram();50         }51     }52 };53 54 class ForenonnState : public State55 {56 public:57     void writeProgram(Work *w)58     {59         if (w->hour < 12)60         {61             cout << "当前时间: " << w->hour << "上午工作精神百倍!" << endl;62         }63         else64         {65             w->current = new AfternoonState();66             w->writeProgram();67         }68     }69 };70 71 Work::Work()72 {73     current = new ForenonnState();74 }75 76 int main()77 {78     Work *w = new Work();79     w->hour = 21;80     w->writeProgram();81     return 0;82 }83 //Reuslt:84 //当前时间: 21心情很好，在看《明朝那些事儿》，收获很大！