roll.txt

操作系统的内存资源的轮转法

#include"stdio.h"
#include"stdlib.h"
#include"string.h"
#include"iostream.h"
typedef struct node
{
char pname[10];
int prio;
//int round;
int cputime;
int needtime;
int servertime;
char state;
struct node *next;
}PCB;
PCB *finish,*ready,*run;
int N;

void printready()
{
    PCB *p;
   if(ready==NULL) printf("******就绪队列为空! \n");
   else
   {
        printf("******就绪队列为:");
        p=ready;
       while(p!=NULL)
    {
           printf("%s---",p->pname);
           p=p->next;
    }
printf(" \n ");
   }
}


void prt1()
{
//if(toupper(a)=='p')
//cout<<" "<<endl;
printf("进程名 已运行时间 剩余时间 要求服务时间    状态\n");
}

void prt2(PCB *q)    /*轮转法的输出*/
{
//if(toupper(a)=='P')
//printf("进程名   已运行时间    剩余时间    要求服务时间    状态");
printf("%3s%10d%12d%12d%12c\n",q->pname,q->cputime,q->needtime,q->servertime,q->state);
}

void prt()
{
PCB *p;
prt1();
if(run!=NULL) prt2(run);
    p=ready;
while(p!=NULL)
{
   prt2(p);
   p=p->next;
}
p=finish;
while(p!=NULL)
{
   prt2(p);
   p=p->next;
}
//getchar();
printready();
}

void insert(PCB *q)
{
    PCB *p1,*s,*r;
    s=q;
    p1=ready;
    r=p1;
while(p1!=NULL)
{
   r=p1;
      p1=p1->next;
}
if(r!=p1)
{
   r->next=s;
      s->next=p1;
}
else
{
   s->next=p1;
      ready=s;
}
}

void create()
{
   PCB *p;
   int i,time;
   //char name[10];
   ready=NULL;
   finish=NULL;
   run=NULL;
// printf("请逐个输入进程名及进程要求运行的时间:\n");
for(i=1;i<=N;i++)
{
     p=new PCB;
printf("*****请逐个输入进程名及进程要求运行的时间:");
     scanf("%s",p->pname);
scanf("%d",&time);
    //strcpy(p->pname,name);
    printf("\n");
    p->cputime=0;
    p->needtime=time;
p->servertime=time;
    p->state='w';
    p->prio=i;
if(ready!=NULL) insert(p);
else
{  
p->next=ready;
ready=p;
}
}
printready();
printf("*****************具体过程如下:******************\n");
run=ready;
ready=ready->next;
run->state='R';
prt();
}

void priority(int T)
{
   while(run!=NULL)
   {
    run->cputime=run->cputime+T;
       run->needtime=run->needtime-T;
       run->prio=run->prio+N;
if(run->needtime==0)
{
run->next=finish;
    finish=run;
    run->state='F';
    run=NULL;
    if(ready!=NULL)
{
run=ready;
run->state='R';
ready=ready->next;
}
}
else
   if(ready!=NULL)
   {
     run->state='W';
     insert(run);
     run=ready;
   run->state='R';
ready=ready->next;
   }
prt();
   }
}


void main()
{
int T;
//char algo='p';
printf("***************时间片轮转调度算法模拟********************\n");
printf("*****请输入进程的个数:");
scanf("%d",&N);
printf("*****请输入轮转时间片周期T:");
scanf("%d",&T);
create();
priority(T);
}