philosphi.cpp

操作系统线程哲学家就餐算法原代码

#include <windows.h>
#include<iostream.h>
#include <stdlib.h>



#define N 5 /* 哲学家的个数 */
#define P(S) WaitForSingleObject(S, INFINITE) // 定义Windows下的P操作
#define V(S) ReleaseSemaphore(S, 1, NULL)  // 定义Windows下的V操作



typedef HANDLE Semaphore; // 信号量的Windows原型
HANDLE  hThread[N];     // 线程计数
Semaphore S[N];         // N根筷子， N个信号量




// 对每个哲学家的线程
DWORD WINAPI Philosopher(LPVOID para)
{
	// i表示第i个哲学家
	int i = *(int *)para, j;
	int period = 100;

	// j只是用来打印缩进用
	char s[10] = "";
	for (j=0; j<i; j++) strcat(s, "\t\t");
	
	//Sleep((N-i)*100);

	while ( 1 )
	{
		Sleep(rand()%1000);
		cout<<s<<"00"<<i<<" think ..."<<endl;
		Sleep(1*period);

		cout<<s<<"00"<<i<<" Hungry"<<endl;

		Sleep(1*period);
		cout<<s<<"00"<<i<<" Get"<<i<<" ..."<<endl;
		P(S[i]);
		Sleep(3*period);
		cout<<s<<"00"<<i<<" Got"<<i<<" OK"<<endl;
		cout<<s<<"00"<<i<<" Get"<<(i+1)%N<<" ..."<<endl;
		P(S[(i+1)%N]);
		cout<<s<<"00"<<i<<" Got"<<(i+1)%N<<" OK"<<endl; 

		cout<<s<<"00"<<i<<" Eating ..."<<endl;
		Sleep(2*period);
		cout<<s<<"00"<<i<<" Eaten."<<endl;

		cout<<s<<"00"<<i<<" Put down"<<i<<endl;
		V(S[i]);

		cout<<s<<"00"<<i<<" Put down"<<(i+1)%N<<endl;
		V(S[(i+1)%N]);

		cout<<endl;
	}
	return 0;
}




int main(int argc, char *argv[])
{
	DWORD tid;
	int i=0;
	char sTmp[32];

	// 初始化信号量
	for (i=0; i<N; i++)
	{
		wsprintf(sTmp, "chopsticks=%d", i);
		S[i] = CreateSemaphore(NULL, 1, 1, sTmp);
		if ( !S[i] )
		{
			cout<<" Create S Error!"<<endl;
			return -1;
		}
	}

	// 开启5个哲学家线程
	for (i=0; i<N; i++)
	{
		hThread[i] = CreateThread(NULL, 0, Philosopher, &i, 0, &tid);
		if ( hThread[i] ) WaitForSingleObject(hThread[i], 10);
	}

	// 等待哲学家执行
	WaitForMultipleObjects(N, hThread, TRUE, INFINITE);
	return 0;
}