q=（pcb*）malloc（sizeof（pcb））;
scanf（"%s",q->name）;
scanf（"%d",&q->needtime）;
q->cputime=0;
q->count=0;
q->process=ready;
q->next=NULL;
if（i==0）{
p=q;
t=q;
}
else{
t->next=q;
t=q;
}
i++;
}
returnp;
}
voidcpu_round（pcb*q）{
if（q->needtime==1）
q->cputime++;
else
q->cputime+=2;
q->needtime-=2;
if（q->needtime<0）{
q->needtime=0;
}
q->count++;
q->process=execute;
}
pcb*get_next（pcb*k,pcb*head）{
pcb*t;
t=k;
do{
t=t->next;
}while（t&&t->process==finish）;
if（t==NULL）{
t=head;
while（t->next!
=k&&t->process==finish）{
t=t->next;}}
returnt;}
voidset_state（pcb*p）{
while（p）{
if（p->needtime==0）{
p->process=finish;
}
if（p->process==execute）{
p->process=ready;}
p=p->next;}}
voiddisplay_round（pcb*p）{
printf（"namecputimeneedtimecountstate\n"）;
while（p）{
printf（"%s",p->name）;
printf（""）;
printf（"%d",p->cputime）;
printf（""）;
printf（"%d",p->needtime）;
printf（""）;
printf（"%d",p->count）;
printf（""）;
switch（p->process）{
caseready:
printf（"ready\n"）;break;
caseexecute:
printf（"execute\n"）;break;
caseblock:
printf（"block\n"）;break;
casefinish:
printf（"finish\n"）;break;}
p=p->next;}}
voidround_cal（）{
pcb*p;
pcb*r;
p=get_process_round（）;
intcpu=0;
r=p;
while（!
process_finish（p））{
if（r->needtime==1）
cpu+=1;
else
cpu+=2;
cpu_round（r）;
r=get_next（r,p）;
printf（"cputime:
%d\n",cpu）;
display_round（p）;
set_state（p）;
sleep
（2）;}
free_process（p）;}
main（）{
display_menu（）;
intk;
scanf（"%d",&k）;
switch（k）{
case1:
priority_cal（）;break;
case2:
round_cal（）;break;
case3:
break;
default:
printf（"YOUHAVENOTCHOOSEANYALGORITHM!
\n"）;
}
}
运行后结果如下：
[root@rhel5hbzy~]#gcc-ochulijichuliji.c
[root@rhel5hbzy~]#./m
CHOOSETHEALGORITHM:
1PRIORITY
2ROUNDROBIN
3EXIT
1
inputnameandtime
jing2
aaaa8
bbbb5
ffff4
ggg6
cputime:
1
namecputimeneedtimeprioritystate
jing-1145execute
aaaa*0842ready
bbbb20050finish
ffff20050finish
ggg0644ready
rtyucputime:
2
namecputimeneedtimeprioritystate
jing*2042execute
aaaa*0842ready
bbbb20050finish
ffff20050finish
ggg0644ready
5cputime:
3
namecputimeneedtimeprioritystate
jing*2042finish
aaaa*0842ready
bbbb20050finish
ffff20050finish
ggg1541execute
2cputime:
4
namecputimeneedtimeprioritystate
jing*2042finish
aaaa'1739execute
bbbb20050finish
ffff20050finish
ggg1541ready
cputime:
5
namecputimeneedtimeprioritystate
jing*2042finish
aaaa'1739ready
bbbb20050finish
ffff20050finish
ggg2438execute
cputime:
6
namecputimeneedtimeprioritystate
jing*2042finish
aaaa$2636execute
bbbb20050finish
ffff20050finish
ggg2438ready
cputime:
7
namecputimeneedtimeprioritystate
jing*2042finish
aaaa$2636ready
bbbb20050finish
ffff20050finish
ggg3335execute
cputime:
8
namecputimeneedtimeprioritystate
jing*2042finish
aaaa!
3533execute
bbbb20050finish
ffff20050finish
ggg3335ready
cputime:
9
namecputimeneedtimeprioritystate
jing*2042finish
aaaa!
3533ready
bbbb20050finish
ffff20050finish
ggg4232execute
cputime:
10
namecputimeneedtimeprioritystate
jing*2042finish
aaaa4430execute
bbbb20050finish
ffff20050finish
ggg4232ready
cputime:
11
namecputimeneedtimeprioritystate
jing*2042finish
aaaa4430ready
bbbb20050finish
ffff20050finish
ggg5129execute
cputime:
12
namecputimeneedtimeprioritystate
jing*2042finish
aaaa5327execute
bbbb20050finish
ffff20050finish
ggg5129ready
cputime:
13
namecputimeneedtimeprioritystate
jing*2042finish
aaaa5327ready
bbbb20050finish
ffff20050finish
ggg6026execute
cputime:
14
namecputimeneedtimeprioritystate
jing*2042finish
aaaa6224execute
bbbb20050finish
ffff20050finish
ggg6026finish
3
cputime:
15
namecputimeneedtimeprioritystate
jing*2042finish
aaaa7121execute
bbbb20050finish
ffff20050finish
ggg6026finish
cputime:
16
namecputimeneedtimeprioritystate
jing*2042finish
aaaa8018execute
bbbb20050finish
ffff20050finish
ggg6026finish
Allprocesseshavefinished
[root@rhel5hbzy~]#rtyu2
bash:
rtyu2:
commandnotfound
[root@rhel5hbzy~]#3
bash:
3:
commandnotfound
三、分析与体会
多道程序设计中，通常是若干个进程同时处于就绪状态，必须依照某种策略来决定哪个进程优先占有处理机。
因而引起进程调度。
本实验模拟单处理机情况下的处理机调度问题，使我加深了对进程调度的理解。
通过本次试验，使我加深了对进程调度的具体细节的理解，掌握LINUX系统结构、实现处理机和各种典型的算法，系统了解了操作系统的设计和实验思路，动手能力更强了。
升级会员 