#include <iostream.h>
class PCB
{
public:
	char pname[20];		//進程名
	int level;			//進程的優先級
	int runtime;		//估計運行時間
	char state;			//進程狀態
	class PCB * next;	//尾鏈接指針
	class PCB * pre;	//頭鏈接指針
public:
	void ShowInf()
	{
		cout<<"進程名:"<<pname<<endl;
		cout<<"運行級:"<<level<<endl;
		cout<<"估計運行時間:"<<runtime<<endl;
		cout<<"進程狀態:"<<state<<endl;
		cout<<endl;
	}
};

PCB pcb[5];
PCB *pcbHead;
PCB *pCurRunProc;
long CurTime;
//創建進程
void CreateProcess()
{

	//鏈接就緒進程頭尾
	pcb[0].next = &pcb[1];
	pcb[1].next = &pcb[2];
	pcb[2].next = &pcb[3];
	pcb[3].next = &pcb[4];
	pcb[4].next = NULL;
	pcb[0].pre = NULL;
	pcb[1].pre = &pcb[0];
	pcb[2].pre = &pcb[1];
	pcb[3].pre = &pcb[2];
	pcb[4].pre = &pcb[3];

	pcbHead = &pcb[0];

	//初始化５個進程信息
	cout<<"請輸入5個進程信息:"<<endl;

	for(int i = 0;i < 5;i++)
	{
		cout<<"請輸入進程"<<i+1<<"的信息:"<<endl;
		cout<<"進程名:";
		cin>>pcb[i].pname;
		cout<<"運行級:";
		cin>>pcb[i].level;
		cout<<"估計運行時間:";
		cin>>pcb[i].runtime;
		pcb[i].state = 'R';
	}
	cout<<endl<<"以下為運行記錄:"<<endl;
}

//選擇進程
int SelectProcess()
{
	int nRC = 0;
	PCB *pcbTemp = pcbHead;
	//如果就緒進程隊列為空，退出
	if( pcbTemp == NULL)
		return 0;
	pCurRunProc = NULL;
	int lv = 65535;
	//從就緒進程隊列中選擇出一個高優先級的進程
	do
	{
		if((pcbTemp->state == 'R') && (pcbTemp->level <= lv))
		{
			lv = pcbTemp->level;
			pCurRunProc = pcbTemp;
		}
		pcbTemp = pcbTemp->next;
	}
	while( pcbTemp != NULL);
	return 1;
}

//運行進程
void RunProcess()
{
	if(pCurRunProc->runtime == 0)
	{
		pCurRunProc->state = 'C';
		//就緒進程頭
		if(pCurRunProc == pcbHead)
		{
			pcbHead = pCurRunProc->next;
			pCurRunProc->pre = NULL;
			pCurRunProc->next = NULL;		
		}
		//就緒進程尾
		else if(pCurRunProc->next == NULL)
		{
			if(pCurRunProc->pre != NULL)
			{
				pCurRunProc->pre->next = NULL;
				pCurRunProc->pre = NULL;
			}
			else
			{
				pcbHead = NULL;
			}
			pCurRunProc->next = NULL;
		}
		//就緒進程中
		else
		{
			pCurRunProc->pre->next = pCurRunProc->next;
			pCurRunProc->next->pre = pCurRunProc->pre;
			pCurRunProc->pre = NULL;
			pCurRunProc->next = NULL;
		}
	}
	else
	{
		pCurRunProc->level++;
		pCurRunProc->runtime--;
		CurTime++;
		cout<<"當前時間:"<<CurTime<<endl;
		pCurRunProc->ShowInf();
	}
	
}

void main()
{
	CurTime = 0;
	CreateProcess();
	int nRun = SelectProcess();
	//當沒有進程可運行時退出
	while( nRun == 1)
	{
		nRun = SelectProcess();
		RunProcess();
	}
	cout<<endl<<"進程運行完畢!"<<endl;
}