面试题-多线程编程

// 222_thread.cpp : 定义控制台应用程序的入口点。//#include "stdafx.h"#include <windows.h>#include <thread>#include <iostream>using namespace std;HANDLE ghMutex;HANDLE handles[4][4];int idxx = 1;void threadA(){    int idx = 0;    do    {        DWORD res = WaitForMultipleObjects(4, handles[0], false, INFINITE);        WaitForSingleObject(ghMutex, INFINITE);        switch (res)        {        case WAIT_OBJECT_0:            cout << "A"  ;            SetEvent(handles[1][0]);            break;        case WAIT_OBJECT_0+1:            cout << "B";            SetEvent(handles[1][1]);            break;        case WAIT_OBJECT_0+2:            cout << "C";            SetEvent(handles[1][2]);            break;        case WAIT_OBJECT_0+3:            cout << "D";            SetEvent(handles[1][3]);            break;        }        cout << 1;        idxx++;        ReleaseMutex(ghMutex);    } while (idxx < 50);    }void threadB(){        int idx = 0;    do    {        DWORD res = WaitForMultipleObjects(4, handles[1], false, INFINITE);        WaitForSingleObject(ghMutex, INFINITE);        switch (res)        {        case WAIT_OBJECT_0:            cout << "A";            SetEvent(handles[2][0]);            break;        case WAIT_OBJECT_0 + 1:            cout << "B";            SetEvent(handles[2][1]);            break;        case WAIT_OBJECT_0 + 2:            cout << "C";            SetEvent(handles[2][2]);            break;        case WAIT_OBJECT_0 + 3:            cout << "D";            SetEvent(handles[2][3]);            break;        }        cout << 2;        idxx++;        ReleaseMutex(ghMutex);    } while (idxx < 50);}void threadC(){    int idx = 0;    do    {        DWORD res = WaitForMultipleObjects(4, handles[2], false, INFINITE);        WaitForSingleObject(ghMutex, INFINITE);        switch (res)        {        case WAIT_OBJECT_0:            cout << "A";            SetEvent(handles[3][0]);            break;        case WAIT_OBJECT_0 + 1:            cout << "B";            SetEvent(handles[3][1]);            break;        case WAIT_OBJECT_0 + 2:            cout << "C";            SetEvent(handles[3][2]);            break;        case WAIT_OBJECT_0 + 3:            cout << "D";            SetEvent(handles[3][3]);            break;        }        cout << 3;        idxx++;        ReleaseMutex(ghMutex);    } while (idxx < 50);}void threadD(){    int idx = 0;    do    {        DWORD res = WaitForMultipleObjects(4, handles[3], false, INFINITE);        WaitForSingleObject(ghMutex, INFINITE);        switch (res)        {        case WAIT_OBJECT_0:            cout << "A";            SetEvent(handles[0][0]);            break;        case WAIT_OBJECT_0 + 1:            cout << "B";            SetEvent(handles[0][1]);            break;        case WAIT_OBJECT_0 + 2:            cout << "C";            SetEvent(handles[0][2]);            break;        case WAIT_OBJECT_0 + 3:            cout << "D";            SetEvent(handles[0][3]);            break;        }        cout << 4;        idxx++;        ReleaseMutex(ghMutex);    } while (idxx < 50);}void WriteA(){    SetEvent(handles[0][0]);}void WriteB(){    SetEvent(handles[1][1]);}void WriteC(){    SetEvent(handles[2][2]);}void WriteD(){    SetEvent(handles[3][3]);}int _tmain(int argc, _TCHAR* argv[]){    /*            file A      file B        file C       file D      thread 1 handle[0][0] handle[0][1] handle[0][2] handle[0][3]       thread 2 handle[1][0] handle[1][1] handle[1][2] handle[1][3]      thread 3 handle[2][0] handle[2][1] handle[2][2] handle[2][3]      thread 4 handle[3][0] handle[3][1] handle[3][2] handle[3][3]    */    for (int i = 0; i < 4; i++)    {        for (int j = 0; j < 4; j++)        {            handles[i][j] = CreateEvent(NULL, false, false, NULL);        }    }    DWORD threadID;    CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)threadA, NULL, 0, &threadID);    CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)threadB, NULL, 0, &threadID);    CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)threadC, NULL, 0, &threadID);    CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)threadD, NULL, 0, &threadID);    CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)WriteA, NULL, 0, &threadID);    CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)WriteB, NULL, 0, &threadID);    CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)WriteC, NULL, 0, &threadID);    CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE)WriteD, NULL, 0, &threadID);    ghMutex = CreateMutex(        NULL,              // default security attributes        FALSE,             // initially not owned        NULL);             // unnamed mutex    if (ghMutex == NULL)    {        printf("CreateMutex error: %d
", GetLastError());        return 1;    }    Sleep(60000);    return 0;}