#include<iostream.h>

//隊列類聲明
class queue 
{
private:
	char *table;
	int size;
	int front,rear;
public:
	queue(int n=0);
	~queue();
	bool isempty();
	bool isfull();
	bool enqueue(const char k);
	char dequeue();
};

//隊列類操作實現(xiàn)
queue::queue(int n)
{
	table=new char[n];
	size=n;
	front=rear=0;
}

queue::~queue()
{
	delete []table;
	size=0;
	front=rear=0;
}

bool queue::isempty()
{
	return front==rear;
}

bool queue::isfull()
{
	return front==rear%size+1;
}

bool queue::enqueue(const char ch)
{
	if(!isfull())
	{
		table[rear]=ch;
		rear=(rear+1)%size;
		return true;
	}
	else
	{
		cout<<"隊列已滿，"<<ch<<"值無法入隊列！"<<endl;
		return false;
	}
}

char queue::dequeue()
{
	char ch=0;
	if(!isempty())
	{
		ch=table[front];
		front=(front+1)%size;
	}
	return ch;
}

void main()
{
	queue q0(20),q1(20),q2(20);  //創(chuàng)建三個隊列，q0為就緒隊列，q1和q2為等待隊列
	int m,i=0;
	char ch,c,c1;
	for(ch='a';ch<='d';ch++)  //依次創(chuàng)建a,b,c,d四個進程進入就緒隊列
		q0.enqueue(ch);
	while(i!=4)
	{
		c=q0.dequeue();
	    cout<<"進程"<<c<<"占有CPU開始運行"<<endl;
		cout<<endl<<"請選擇:"<<endl
			<<"0:進程完成，操作系統(tǒng)釋放該進程"<<endl
			<<"1:等待事件1發(fā)生，進程入事件1等待隊列"<<endl
			<<"2:等待事件2發(fā)生，進程入事件2等待隊列"<<endl
			<<"3:運行時間片到，進程入就緒隊列"<<endl;
	    cin>>m;
	    switch(m)
		{
	    case 0: cout<<"進程"<<c<<"完成"<<endl; 
			    i++;
		        break;
	    case 1: cout<<"等待事件1發(fā)生,進程"<<c
				<<"入事件1等待隊列"<<endl;
		        q1.enqueue(c);
			    cout<<"事件1是否出現(xiàn)?(y/n)\n";
			    cin>>c1;
			    if(c1=='y')
				{
					q0.enqueue(q1.dequeue());
                    cout<<"進程"<<c<<"入就緒隊列"<<endl;
				}
			    break;
	    case 2: cout<<"等待事件2發(fā)生,進程"<<c
				<<"入事件2等待隊列"<<endl;
		        q2.enqueue(c);
			    cout<<"事件2是否出現(xiàn)?(y/n)\n";
			    cin>>c1;
			    if(c1=='y')
				{
				    q0.enqueue(q2.dequeue());
                    cout<<"進程"<<c<<"入就緒隊列"<<endl;
				}
		    	break;
	    case 3: cout<<"運行時間片到,進程"<<c<<"入就緒隊列\(zhòng)n";
		        q0.enqueue(c);
		        break;
	    default:cout<<"錯誤!"<<endl;
		        break;
		}
	}
}