lun.cpp

处理机调度的算法

#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include "time.h"
#include <iostream.h>
int num=0;
typedef struct node
{
   char name[10];  /*进程标识符*/
   int round;  /*进程时间轮转时间片*/
   int cputime; /*进程占用CPU时间*/
   int needtime; /*进程到完成还要的时间*/
   int count;  /*计数器*/
   char state; /*进程的状态*/
   struct node *next; /*链指针*/
   int ftime;
   int T;
   int W;
}PCB;
PCB *finish,*ready,*tail,*run; /*队列指针*/
int N; /*进程数*/
char *output[100];
int point=0;
/*将就绪队列中的第一个进程投入运行*/
void firstin()
{
   run=ready;   /*就绪队列头指针赋值给运行头指针*/
   run->state='R';   /*进程状态变为运行态*/
   ready=ready->next;  /*就绪对列头指针后移到下一进程*/
}

void prt1()
{
      printf("  name     cputime  needtime   count   round     state\n");
}
/*进程PCB输出*/
void prt2(PCB *q)
{
       printf("  %-10s%-10d%-10d%-10d%-10d %-c\n",q->name,
       q->cputime,q->needtime,q->count,q->round,q->state);
}
/*输出函数*/
void prt()
{
   PCB *p;
   prt1();  /*输出标题*/
   if(run!=NULL) /*如果运行指针不空*/
   prt2(run); /*输出当前正在运行的PCB*/
   p=ready;  /*输出就绪队列PCB*/
   while(p!=NULL)
   {
      prt2(p);
      p=p->next;
   }
   p=finish;  /*输出完成队列的PCB*/
   while(p!=NULL)
   {
      prt2(p);
      p=p->next;
   }
   
}
/*插入函数*/
void insert2(PCB *p2)
{
   tail->next=p2;  /*将新的PCB插入在当前就绪队列的尾*/
   tail=p2;
   p2->next=NULL;
}

/*创建进程PCB*/
void create()
{
   PCB *p;
   int i,time;
   char na[10];
   ready=NULL;
   finish=NULL;
   run=NULL;
   printf("请输入进程名和执行时间\n");
   for(i=1;i<=N;i++)
   {
      p=(PCB*)malloc(sizeof(PCB));
      scanf("%s",na);
      scanf("%d",&time);
      strcpy(p->name,na);
      p->cputime=0;
      p->needtime=time;
      p->count=0; 
      p->state='w';
      p->round=2; 
	    p->ftime=0;
	    p->T=0;
	    p->W=0;
      if(ready!=NULL)
      insert2(p);
      else
      {
       p->next=ready;
       ready=p;
       tail=p;
      }
   }
	   printf("          轮转法处理机调度过程\n");
	   printf("************************************************\n");
	   prt();   /*输出进程PCB信息*/
	   run=ready;  /*将就绪队列的第一个进程投入运行*/
	   ready=ready->next;
	   run->state='R';
}
/*时间片轮转法*/
void roundrun()
{
   while(run!=NULL)
   {

      run->cputime=run->cputime+1;
	    num++;
      run->needtime=run->needtime-1;
      run->count=run->count+1;

      if(run->needtime==0)/*运行完将其变为完成态，插入完成队列*/
      {
	      output[point]=run->name;
		    point++;
			  run->next=finish;
			  finish=run;
			  run->ftime=num;
			  run->state='F';
			  run=NULL;
        if(ready!=NULL)
        firstin(); /*就绪对列不空，将第一个进程投入运行*/
		    prt();
      }
      else
	  if(run->count==run->round)  /*如果时间片到*/
	  {
			run->count=0;  /*计数器置0*/
	 		output[point]=run->name;
			point++;
		 if(ready!=NULL) /*如就绪队列不空*/
		 {
			run->state='W'; /*将进程插入到就绪队列中等待轮转*/
			insert2(run);
			firstin(); /*将就绪对列的第一个进程投入运行*/
		 }
			prt();
	  }

   }
}
/*主函数*/
void main()
{
	int i=0;
	for(;i<100;i++)
	{
		output[i]="";
	}
	int temp=0,temp2=0;
    srand((unsigned)time(NULL));
	while(N<2 || N>6)
	N=(int)(100*rand()/(RAND_MAX+1.0))+1;
    printf("进程数为%d\n",N);

    create(); /*轮转法*/
    roundrun();

   while(finish->next!=NULL)
  {
	  
	  finish->T=finish->ftime;
	  temp+=finish->T;
	  finish->W=finish->ftime/finish->cputime;
	  temp2+=finish->W;
	  finish=finish->next;

  }
      finish->T=finish->ftime;
	  temp+=finish->T;
	  finish->W=finish->ftime/finish->cputime;
	  temp2+=finish->W;

	  cout<<"进程的执行顺序是：";
	  for(i=0;i<point-1;i++)
	  {
		  cout<<output[i]<<"->";
	  }
	  cout<<output[i]<<endl;

      printf("平均周转时间=%f\n平均带权周转时间=%f\n",(float)temp/(float)N,(float)temp2/(float)N);
      getchar();
}