操作系统用C语言模拟基于时间片进程调度程序

#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

{

9900

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() ;

}