#include <windows.h>
#include <process.h>
#include <iostream>
#include <fstream>
#include <cstdlib>
#include <ctime>
#include <time.h>
using namespace std;
//------------------------------------------------------
unsigned int n1; //总的计算次数
unsigned int thread_count=2; //线程的个数
unsigned int n2; //总的成功点数
HANDLE mutex; //互斥变量
//-----------------------------------------------------
bool judge_n(double x,double y)//判断是否落在圆弧内
{
if(x*x+y*y<=1)
return true;
return false;
}
//------------------------------------------------------
DWORD WINAPI GetPi(LPVOID parma)
{
unsigned int i=0;
unsigned int n = 0;
double x=0,y=0;
for(;i<100000000/thread_count;i++)
{
x=(double)rand()/RAND_MAX;//获得随机数
y=(double)rand()/RAND_MAX;//获得随机数
if(judge_n(x,y))
n2++;
n1++;
}
WaitForSingleObject(mutex,INFINITE);
ReleaseMutex(mutex);
double Pi=4*(double)n2/(double)n1;
printf("π=%f\n",Pi);
HANDLE hSemaphore = OpenSemaphore(SEMAPHORE_ALL_ACCESS,TRUE,L"MySemaphore");
ReleaseSemaphore(hSemaphore,1,NULL);
return 0;
}
//-------------------------------------------------------------------
void main()
{
HANDLE * thread; double start,finish;
start=(double)clock()/CLOCKS_PER_SEC;//记录运行前的系统时间
Sleep(1000); //睡眠10s
thread = new HANDLE[thread_count];
mutex=CreateMutex(NULL,FALSE,L"MyMutex");
HANDLE Finish = CreateSemaphore(NULL,0,1,L"MySemaphoer");
printf("线程计算结果：\n");
for(unsigned int i=0;i<thread_count;i++)
thread[i]=CreateThread(NULL,0,GetPi,NULL,0,0);
WaitForMultipleObjects(thread_count,thread,TRUE,INFINITE);
cout<<endl<<"π="<<4.0*(double)n2/(double)n1<<endl;
finish = (double)clock()/CLK_TCK;//记录运行后的系统时间
delete []thread;
cout<<"time=" << finish-start <<"s" << endl;//显示程序运行的时间
}
