题目:
四个线程 t1,t2,t3,t4,向 4 个文件中写入数据， t1 只能写入 1， t2 只能写入 2， t3 只能写
入 3， t4 只能写入 4，对 4 个文件 A， B， C， D 写入如下内容
A:123412341234.....
B:234123412341....
C:341234123412....
D:412341234123....
怎么实现同步可以让线程并行工作？
用windows c++实现.
// 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 Dthread 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 attributesFALSE, // initially not ownedNULL); // unnamed mutexif (ghMutex == NULL){printf("CreateMutex error: %d\n", GetLastError());return 1;}Sleep(60000);return 0; }