实验一 ：WindowsThreads多线程编程.docVIP

实验 ：Windows*Threads多线程编程 模块一：基础练习 4 编译执行， 输出结果： 简答与思考： 写出修改后的HelloThreads的代码。 #include stdafx.h #include windows.h const int numThreads = 4; DWORD WINAPI helloFunc(LPVOID pArg) { int myNum=*((int*)pArg); printf(Hello Thread %d \n,myNum); return 0; } int main() { HANDLE hThread[numThreads]; int tNum[10]; for (int i = 0; i numThreads; i++) { tNum[i]=i; hThread[i] = CreateThread(NULL, 0, helloFunc, tNum[i], 0, NULL ); }WaitForMultipleObjects(numThreads, hThread, TRUE, INFINITE); return 0; } 修改后结果 2实验总结 模块二：临界区实验 编译执行， Pi的值为： 编译执行，Pi的值为： 简答与思考： 1 如何进行并行化的？请写出并行化的思路与具体的代码。 // WinPi.cpp : 定义控制台应用程序的入口点 // #include stdafx.h #include windows.h #include time.h static long num_steps=1000000000; double step, pi; CRITICAL_SECTION gCS; //定义全局的临界变量gCS const int numThreads = 2; double dAllSum; DWORD WINAPI PiCalculationThread(LPVOID p) { int j = *(int *)p; double dSum = 0; double dx; int ii; printf(This is the thread %d computing:\n,j); for( ii = j ; ii num_steps ; ii+=numThreads ){ dx = (ii+0.5)*step; dSum = dSum + 4.0/(1.0 + dx*dx); } EnterCriticalSection(gCS); //进入临界区 dAllSum += dSum; LeaveCriticalSection(gCS); //离开临界区 printf(The thread %d computation has finished:\n,j); return 0; } int _tmain(int argc, _TCHAR* argv[]) { clock_t start1; clock_t stop1; start1= clock(); //开始计时 HANDLE PiCalculation[numThreads]; int tmp[numThreads]; step = 1.0/(double) num_steps; InitializeCriticalSection(gCS); for( int ia = 0 ; ia numThreads ; ia++ ){ tmp[ia] = ia; PiCalculation[ia] = CreateThread(NULL , 0 , PiCalculationThread , tmp[ia] , 0 , NULL); } WaitForMultipleObjects (numThreads,PiCalculation,TRUE,INFINITE); DeleteCriticalSection(gCS); pi = step * dAllSum; printf(Pi = %12.9f\n,pi); stop1 = clock(); //停止计时 printf(The time of calculation was %f seconds \n,(double)(stop1 - start1)/1000.0); //输出运行时间 } 2 在本实验中，哪些变量是需要保护的？采取什么方法实现的？ dAllSum变量需要保护 EnterCriticalSection(gCS); //进入临界区 dAllSum += d