多线程经典问题-----乘客做公交车问题解答1

1.问题描述：

//车辆行驶问题，司机，乘客售票员协同工作

//司机：开车，停车

//售票员：打开车门，关闭车门

//乘客：上车，下车

解答1：

通过使用CEvent 事件类，模拟三者协同工作。下面的程序只模拟了乘客上车的情况。没有考虑乘客下车。

主程序如下：

#define  PASSENGERCOUNT 20
class CPassengerBusQuestion
{
public:
CPassengerBusQuestion(void);
virtual ~CPassengerBusQuestion(void);

private:
CCriticalSection m_cs;
public:

CWinThread *m_pDriverThread;
CWinThread *m_pConductorThread;
CWinThread *m_pPassengerThreadArr[PASSENGERCOUNT];
HANDLE m_eventBusStop;
HANDLE m_eventConductorClosedoor;
HANDLE m_eventConductorOpenDoor;

int m_nTotalStation;
int m_nCurStationIndex;
public:
void Init();
static UINT Driver_Proc(LPVOID lpParam);
static UINT Conductor_Proc(LPVOID lpParam);
static UINT Passenger_Proc(LPVOID lpParam);

private:
void OutputLog(char *format,...);

};

 

static char StationName[7][20] =
{
"车站1",
"车站2",
"车站3",
"车站4",
"车站5",
"车站6",
};

typedef struct tagThreadParam
{
CPassengerBusQuestion *pBusQuestion;
int index;// Passenger NO.
int nGetOnStation;//The tation NO Passenger gets on.
BOOL bLastPerson;//if Passenger is the Last Person
}ThreadParam;

void CPassengerBusQuestion::Init()
{
m_nTotalStation = 4;
m_nCurStationIndex = -1;
m_pDriverThread = NULL;
m_pConductorThread = NULL;
m_eventConductorOpenDoor = NULL;
m_eventConductorClosedoor = NULL;
m_eventBusStop = NULL;

m_eventBusStop = ::CreateEvent(NULL,FALSE,FALSE,NULL);
m_eventConductorClosedoor = ::CreateEvent(NULL,FALSE,FALSE,NULL);
m_eventConductorOpenDoor  = ::CreateEvent(NULL,TRUE,FALSE,NULL);

m_pDriverThread = AfxBeginThread(CPassengerBusQuestion::Driver_Proc,this,THREAD_PRIORITY_NORMAL,0,CREATE_SUSPENDED);
m_pConductorThread = AfxBeginThread(CPassengerBusQuestion::Conductor_Proc,this,THREAD_PRIORITY_NORMAL,0,CREATE_SUSPENDED);
for(int i =0;i< PASSENGERCOUNT;i++)
{
ThreadParam* pParam =new ThreadParam;
pParam->pBusQuestion = this;
pParam->index = i;
pParam->nGetOnStation = i%5;

m_pPassengerThreadArr[i] = AfxBeginThread(CPassengerBusQuestion::Passenger_Proc,pParam,THREAD_PRIORITY_NORMAL,0,CREATE_SUSPENDED);
}

m_pDriverThread->ResumeThread();
m_pConductorThread->ResumeThread();

for(int i =0;i<PASSENGERCOUNT;i++)
{
m_pPassengerThreadArr[i]->ResumeThread();
}
}

各个人员（线程）的业务逻辑如下：

//司机线程
UINT CPassengerBusQuestion::Driver_Proc(LPVOID lpParam)
{
bool bExitThread=false;
CPassengerBusQuestion* pBusQuestion =(CPassengerBusQuestion *)lpParam;

while(!bExitThread)
{
pBusQuestion->OutputLog("司机：车辆开始行驶....\n");
::Sleep(5000);
pBusQuestion->OutputLog("司机：到站\n");
pBusQuestion->m_nCurStationIndex++;

SetEvent(pBusQuestion->m_eventBusStop);
::WaitForSingleObject(pBusQuestion->m_eventConductorClosedoor,INFINITE);
if( pBusQuestion->m_nCurStationIndex == pBusQuestion->m_nTotalStation)
{
bExitThread = TRUE;
}

}
return 0;
}

//售票员线程
UINT CPassengerBusQuestion::Conductor_Proc(LPVOID lpParam)
{
bool bExitThread = false;
CPassengerBusQuestion* pBusQuestion =(CPassengerBusQuestion *)lpParam;

while(!bExitThread)
{
::WaitForSingleObject(pBusQuestion->m_eventBusStop,INFINITE);//等待司机停车
pBusQuestion->OutputLog("售票员：打开车门\n");
pBusQuestion->OutputLog("售票员：%s到了\n", StationName[pBusQuestion->m_currentStationIndex]);
SetEvent(pBusQuestion->m_eventConductorOpenDoor);
::Sleep(3000);	//等待乘客上下车。
::ResetEvent(pBusQuestion->m_eventConductorOpenDoor);//此事件只能手工制，不能自动置，手工也不能交给某一个乘客。
pBusQuestion->OutputLog("售票员：关闭车门\n");
SetEvent(pBusQuestion->m_eventConductorClosedoor);

if( pBusQuestion->m_nCurStationIndex == pBusQuestion->m_nTotalStation)
{
bExitThread = TRUE;
}

}

return 0;
}

//乘客线程
UINT CPassengerBusQuestion::Passenger_Proc(LPVOID lpParam)
{
ThreadParam* pParam = (ThreadParam *)lpParam;
int index = pParam->index;  //第几号乘客；
int nGetOnStation = pParam->nGetOnStation;  //第几站上车
BOOL bLastPerson  = pParam->bLastPerson;//是否是最后一个上车的人
CPassengerBusQuestion *pBusQuestion = pParam->pBusQuestion;
delete pParam;

bool bExitThread = false;
while(!bExitThread)
{
::WaitForSingleObject(pBusQuestion->m_eventConductorOpenDoor,INFINITE);
if(pBusQuestion->m_nCurStationIndex == nGetOnStation)//判断公交车是否到车站了。
{
pBusQuestion->OutputLog("乘客%d:在 %s已经上车\n",index,StationName[nGetOnStation]);
bExitThread = TRUE;
}
::Sleep(1000);
}
return 0;
}

 

//辅助函数
void CPassengerBusQuestion::OutputLog( char *format,... )
{
m_cs.Lock();
char temp[1024]={0};
va_list arg_ptr;
va_start(arg_ptr, format);
int nWrittenBytes = vsprintf(temp, format, arg_ptr);
va_end(arg_ptr);
printf(temp);
m_cs.Unlock();
}

输出结果如下：