process.cpp

这个是编译原理课程的词法分析器

// process.cpp : 定义控制台应用程序的入口点。

#include <stdio.h>
#include <dos.h>
#include <stdlib.h>
#include <conio.h>
#include <iostream.h>
#define PROCESS_NUM 5
#define PROCESS_TIME 50

/*
 * 进程状态
 */
enum state{
	ready,
	execute,
	block,
	finish
};

/*
 * 进程控制块
 */
struct pcb{
	char pname[4];
	int priority;
	int cputime;
	int needtime;
	int count;
	int round;
	state pstate;
	pcb * next;
};

/*
 * 创建进程控制块链表
 */
pcb * createProcess(){
	pcb *q;
	pcb *t;
	pcb *p;
	int i=0;
	cout<<"输入进程名和时间"<<endl;

	while (i<PROCESS_NUM){
		q=(struct pcb *)malloc(sizeof(pcb));
		cin>>q->pname;
		cin>>q->needtime;
		q->cputime=0;
		q->priority=PROCESS_TIME-q->needtime;
		q->pstate=ready;
		q->next=NULL;
		if (i==0){
			p=q;
			t=q;
		}
		else{
			t->next=q;
			t=q;
		}
		i++;
	}  
	return p;
}

/*
 * 显示全部进程状态
 */
void  display(pcb *p){
	cout<<"进程名"<<"    "<<"CPU时间"<<"    "<<"所需时间"
	<<"    "<<"进程优先级"<<"    "<<"进程状态"<<endl;
	while(p){
		cout<<p->pname;
		cout<<"        ";
		cout<<p->cputime;
		cout<<"          ";
		cout<<p->needtime;
		cout<<"          ";
		cout<<p->priority;
		cout<<"          ";
		switch(p->pstate){
			case ready:cout<<"就绪态"<<endl;break;
			case execute:cout<<"执行态"<<endl;break;
			case block:cout<<"阻塞态"<<endl;break;
			case finish:cout<<"完成态"<<endl;break;
		}
		p=p->next;
	}
}

/*
 * 进程完成
 */
int finishProcess(pcb *q){
	int bl=1;
	while(bl&&q){
		bl=bl&&q->needtime==0;
		q=q->next;
	}
	return bl;
}

/*
 * 执行进程
 */
void executeProcess(pcb *q){
	pcb *t=q;
	int tp=0;
	while(q){
		if (q->pstate!=finish){
			q->pstate=ready;
			if(q->needtime==0){
				q->pstate=finish;
			}
		}
		if(tp<q->priority&&q->pstate!=finish){
			tp=q->priority;
			t=q;
		}
		q=q->next;
	}
	if(t->needtime!=0){
		t->priority-=3;
		t->needtime--;
		t->pstate=execute;
		t->cputime++;
	}
}

/*
 * 计算进程新的优先级
 */
void calculatePriority(){
	pcb * p;
	// clrscr();
	p=createProcess();
	int cpu=0;
	// clrscr();
	while(!finishProcess(p)){
		cpu++;
		cout<<"cputime:"<<cpu<<endl;
		executeProcess(p);
		display(p);
		// sleep(2);
		// clrscr();
	}
	printf("所有进行已经处理完毕!");
	getch();
}

/*
 * 显示主菜单
 */
void displayMenu(){
	cout<<"选择进行调度算法:"<<endl;
	cout<<"1. 优先级调度算法"<<endl;
	cout<<"2. 循环轮转调度算法"<<endl;
	cout<<"3. 退出"<<endl;
}

/*
 * 得到进程轮回次数
 */
pcb* getProcessRound(){
	pcb *q;
	pcb *t;
	pcb *p;
	int i=0;
	cout<<"输入进程名和时间"<<endl;

	while (i<PROCESS_NUM){
		q=(struct pcb *)malloc(sizeof(pcb));
		cin>>q->pname;
		cin>>q->needtime;
		q->cputime=0;
		q->round=0;
		q->count=0;
		q->pstate=ready;
		q->next=NULL;
		if (i==0){
			p=q;
			t=q;
		}
		else{
			t->next=q;
			t=q;
		}
		i++;
	}  //while
	return p;
}

/*
 * 增加进程轮回
 */
void addProcessRound(pcb *q){
	q->cputime+=2;
	q->needtime-=2;
	if(q->needtime<0) {
		q->needtime=0;
	}
	q->count++;
	q->round++;
	q->pstate=execute;

}

/*
 * 获得下一个进程PCB
 */
pcb * getNextPCB(pcb * k,pcb * head){
	pcb * t;
	t=k;
	do{
	 t=t->next;
	}
	while (t && t->pstate==finish);

	if(t==NULL){
		t=head;

		while (t->next!=k && t->pstate==finish){
			t=t->next;
		}
	}
	return t;
}

/*
 * 设定进程状态
 */
void setProcessState(pcb *p){
	while(p){
		if (p->needtime==0){
			p->pstate=finish;

		}
		if (p->pstate==execute){
			p->pstate=ready;
		}
		p=p->next;
	}
}

/*
 * 显示进行轮回
 */
void displayRound(pcb *p){
	cout<<"进程名"<<"  "<<"CPU时间"<<"  "<<"所需时间"
	<<"  "<<"计数"<<"  "<<"轮回次数"<<"  "<<"进程状态"<<endl;
	while(p){
		cout<<p->pname;
		cout<<"      ";
		cout<<p->cputime;
		cout<<"     ";
		cout<<p->needtime;
		cout<<"         ";
		cout<<p->count;
		cout<<"        ";
		cout<<p->round;
		cout<<"       ";
		switch(p->pstate){
			case ready:cout<<"ready"<<endl;break;
			case execute:cout<<"execute"<<endl;break;
			case finish:cout<<"finish"<<endl;break;
		}
		p=p->next;
	}
}

/*
 * 计算进程轮回次数
 */
void calculateRound(){
	pcb * p;
	pcb * r;
	// clrscr();
	p=getProcessRound();
	int cpu=0;
	// clrscr();
	r=p;
	while(!finishProcess(p)){
		cpu+=2;
		addProcessRound(r);
		r=getNextPCB(r,p);
		cout<<"cpu "<<cpu<<endl;
		displayRound(p);
		setProcessState(p);
		// sleep(5);
		// clrscr();
	}
}

/*
 * 主程序
 */
void main(){
	displayMenu();
	int k;
	scanf("%d",&k);
	switch(k){
			case 1:calculatePriority();break;
			case 2:calculateRound();break;
			case 3:break;
			displayMenu();
			scanf("%d",&k);
	}
}