操作系统用C语言模拟基于时间片进程调度程序

时间:2021-08-04 19:52:06
#include<stdio.h>
#include <stdlib.h>    
typedef struct pcb   
{
char name[5];      
int arrivetime;  //到达时间          
int runtime;  //运行时间
int time;
int finishtime; //完成时间
char state;    //状态      
struct pcb* next;     
}PCB;      

PCB *ready = NULL, *p;  

void show(PCB* p); 

int maxnumber(PCB *p);

void paixu()      
{
PCB *first, *second;
int insert = 0;         
if ((ready == NULL) || ((p->arrivetime) < (ready->arrivetime)))   
{
p->next = ready;   
ready = p;        
 
}
else        
{
first = ready;
second = first->next;
while (second != NULL)
{
if (p->arrivetime < second->arrivetime)
{
p->next = second;
first->next = p;
insert = 1;
break;
}
else
{
first = first->next;
second = second->next;
}
}
if (insert == 0) 
{
first->next = p;
p->next = NULL;
}
}
}

void shuru()                
{
int i,j,t1,t2;
printf("\n请输入进程个数:");
 
scanf("%d",&j);
for(i=1;i<=j;i++)         
{  printf("\n第%d个进程\n",i);
p=(PCB*)malloc(sizeof(PCB));      
printf("\n输入进程名:");
scanf("%s",p->name);
printf("\n输入进程需运行时间:");
scanf("%d",&t1);
p->runtime=t1;
       printf("\n输入进程到达时间:");
  scanf("%d",&t2);
       p->arrivetime=t2; 
       p->state='R';
       p->next=NULL;
       paixu(); 
}
     printf("按到达时间进行排序!\n"); 
 p = ready;
    while (p != NULL)      
{
 show(p);
 p = p->next;
}
}

void show(PCB* p)          /*建立进程显示函数*/ 

   printf("name  arrivetime  runtime  state\n");
   printf("%s\t",p->name);
   printf("%d\t\t",p->arrivetime);
   printf("%d\t",p->runtime);
   printf("%c\t\n",p->state);
}
int maxnumber(PCB *p)
{
int max;
max=p->arrivetime;
while(p->next!=NULL)
{
if(max<p->next->arrivetime)
{
max=p->next->arrivetime;
}
p=p->next;
}
return(max);
}

void run()
{
PCB *t,*q,*s;
float sum1=0.0;
 
int time=0,a,sum=0,n=0;
while(p->next!=NULL)
{
p=p->next;
q=p;
}
printf("进程的调度开始!\n");


p=ready;
       s=p;


       a=maxnumber(p);
while(p!=NULL)
{
if(p->state=='C')
{
break;
}
       while(s!=NULL)
  {


    n=n+1;
   // printf("进程名为%s,调度时间为%d\n",s->name,++a);
s->time=s->runtime;
     s=s->next;
  }
     
      printf("进程%s运行一次\n",p->name);
      p->runtime--;
       time=time+1;
p->finishtime=time+a;
               if(p->runtime==0)
  {
     p->state='C';
 printf("进程名为%s,其周转时间为 %d\n",p->name,(p->finishtime)-p->arrivetime);
    
                          sum+=(p->finishtime)-(p->arrivetime);
 
                         printf("进程名为%s的带权周转时间%f\n",p->name,((p->finishtime)-(p->arrivetime))*1.0/(p->time));
sum1+=(time*1.0)/(p->time);
 p=p->next;
                    
               
  }
                 else
                {
                      
                  t=p;
q->next=p;
q=p;
                 p=t->next;
                 }




}
                         
printf("平均周转时间为%f\n",sum*1.0/n);
printf("平均带权周转时间%f\n",sum1*1.0/n);
  
}
               
void  main()
{

   shuru();
   p = ready;    
   run() ;

}