目錄

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基本概念

代碼與實例

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基本概念

狀態模式（State）：當一個對象的內在狀態改變時允許改變其行為，這個對象看起來就像是改變了其類；

狀態模式的好處：

? ? ? ? ? 1. 將與特定狀態相關的行為局部化，并且將不同狀態的行為分割開來；

? ? ? ? ? 2. 狀態模式通過把各種狀態轉移邏輯分布到State的子類之間，來減少相互的依賴；

當一個對象的行為取決與他的狀態，并且他必須在運行時刻根據狀態改變他的行為時，就可以考慮使用狀態模式。

下面舉個例子，UML圖如下（來源大話設計模式）

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代碼與實例

普通的情況：

加班的情況：

Head.h

#ifndef HEAD_H #define HEAD_H#include <iostream> #include <string> using namespace std;class Work;//定義一個抽象方法，寫程序 class State{public:virtual void writeProgram(Work *w){}virtual ~State(){} };//上午和中午工作狀態 class ForenoonState : public State{public:void writeProgram(Work *w);~ForenoonState(); };//中午工作狀態 class NoonState : public State{public:void writeProgram(Work *w);~NoonState(); };//下午工作 class AfternoonState : public State{public:void writeProgram(Work *w);~AfternoonState(); };//晚間工作狀態 class EveningState : public State{public:void writeProgram(Work *w);~EveningState(); };//下班狀態 class RestState: public State{public:void writeProgram(Work *w);~RestState(); };//休眠狀態 class SleepingState : public State{public:void writeProgram(Work *w);~SleepingState(); };//工作類 class Work{public:Work();~Work();void setHour(const double &h);double getHour();void setTaskFinished(const bool &f);bool getTaskFinished();void setState(State *s);void writeProgram();private:State *current;double hour;bool finish; };#endif // !HEAD_H

Head.cpp

#include "Head.h"void ForenoonState::writeProgram(Work *w) {if(w->getHour() < 12){cout << "當前時間：" << w->getHour() << "點 上午工作，精神百倍！" << endl;}else{w->setState(new NoonState());w->writeProgram();} }ForenoonState::~ForenoonState() {cout << "ForenoonState::~ForenoonState() desconstruction !" << endl; }void NoonState::writeProgram(Work *w) {if(w->getHour() < 13){cout << "當前時間：" << w->getHour() << "點 餓了，午飯；犯困，午休。" << endl;}else{w->setState(new AfternoonState());w->writeProgram();} }NoonState::~NoonState() {cout << "NoonState::~NoonState() desconstruction !" << endl; }Work::Work() {this->current = new ForenoonState();this->finish = false;this->hour = 6.0; }Work::~Work() {cout << "Work::~Work() desconstruction !" << endl; }void Work::setHour(const double &h) {this->hour = h; }double Work::getHour() {return this->hour; }void Work::setTaskFinished(const bool &f) {this->finish = f; }bool Work::getTaskFinished() {return this->finish; }void Work::setState(State *s) {if(this->current != nullptr){delete current;//current = nullptr; //這里有點 脫褲子 放屁}this->current = s; }void Work::writeProgram() {this->current->writeProgram(this); }void AfternoonState::writeProgram(Work *w) {if(w->getHour() < 17){cout << "當前時間：" << w->getHour() << "點 下午狀態不錯，繼續努力！！！" << endl;}else{w->setState(new EveningState());w->writeProgram();} }AfternoonState::~AfternoonState() {cout << "AfternoonState::~AfternoonState() desconstruction !" << endl; }void SleepingState::writeProgram(Work *w) {cout << "當前時間：" << w->getHour() << "點 不行了，睡著了" << endl; }SleepingState::~SleepingState() {cout << "SleepingState::~SleepingState() desconstruction !" << endl; }void RestState::writeProgram(Work *w) {cout << "當前時間：" << w->getHour() << "點 下班回家！o(∩_∩)o 哈哈" << endl; }RestState::~RestState() {cout << "RestState::~RestState() desconstruction !" << endl; }void EveningState::writeProgram(Work *w) {if(w->getTaskFinished()){ //下班休息w->setState(new RestState());w->writeProgram();}else{if(w->getHour() < 21){cout << "當前時間：" << w->getHour() << "點 加班中，疲憊至極。" << endl;}else{w->setState(new SleepingState());w->writeProgram();}} }EveningState::~EveningState() {cout << "EveningState::~EveningState() desconstruction !" << endl; }

main.cpp

#include "Head.h"int main(int *argc, int *argv){Work *emergencyPro = new Work();emergencyPro->setHour(9);emergencyPro->writeProgram();emergencyPro->setHour(10);emergencyPro->writeProgram();emergencyPro->setHour(11);emergencyPro->writeProgram();emergencyPro->setHour(12);emergencyPro->writeProgram();emergencyPro->setHour(13);emergencyPro->writeProgram();emergencyPro->setHour(17);emergencyPro->writeProgram();emergencyPro->setHour(19);emergencyPro->writeProgram();emergencyPro->setHour(22);emergencyPro->writeProgram();delete emergencyPro;//Work *normalPro = new Work();//normalPro->setHour(9);//normalPro->writeProgram();//normalPro->setHour(11);//normalPro->writeProgram();//normalPro->setHour(12);//normalPro->writeProgram();//normalPro->setHour(13);//normalPro->writeProgram();//normalPro->setHour(14);//normalPro->writeProgram();//normalPro->setTaskFinished(true);//normalPro->setHour(15);//normalPro->writeProgram();//normalPro->setHour(17);//normalPro->writeProgram();//delete normalPro;getchar();return 0; }

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