代码实现了模拟进程状态转换及其相应PCB内容、组织结构的变化。
#include<iostream>
using namespace std;
typedef struct pcb{
int id;
struct pcb *next;
}pcb;
pcb *ready,*run,*block;
pcb* cre()//创建带头结点的ready队列
{
pcb *head=new pcb;
head->next=NULL;
pcb *q=head;
int n;
cout<<"输入进程数:\n";
cin>>n;
for(int i=0;i<n;i++)
{
pcb *p=new pcb;
cin>>p->id;
p->next=NULL;
q->next=p;
q=p;
}
return head;
}
void ins(pcb *head,pcb *node)//插入节点
{
pcb *p=head;
while(p->next)
{
p=p->next;
}
pcb *n=new pcb;
n->id=node->id;
p->next=n;
n->next=NULL;
}
void del(pcb *head)
{
pcb *p=head->next;
if(p)
{
head->next=head->next->next;
delete p;
}
}
void dis()
{
pcb *p;
p=ready->next;
cout<<"ready:\t";
while(p)
{
cout<<p->id<<" ";
p=p->next;
}
cout<<endl;
p=run->next;
cout<<"run :\t";
while(p)
{
cout<<p->id<<" ";
p=p->next;
}
cout<<endl;
p=block->next;
cout<<"block:\t";
while(p)
{
cout<<p->id<<" ";
p=p->next;
}
cout<<endl;
}
int main()
{
ready=cre();
run=new pcb;
run->next=NULL;
block=new pcb;
block->next=NULL;
dis();
int i;
cout<<"chose:\t1:ready->run\t2:run->ready\t3:run->block\t4:block->ready\n";
while(cin>>i)
{
if(i==1)
{
if(ready->next)
{
if(run->next)
{
ins(block,run->next);
del(run);
}
ins(run,ready->next);
del(ready);
}
else
{
if(block->next)
{
ins(block,run->next);
del(run);
ins(run,block->next);
del(block);
}
}
}
else if(i==2)
{
if(run->next)
{
if(ready->next)
{
ins(ready,run->next);
del(run);
ins(run,ready->next);
del(ready);
}
}
}
else if(i==3)
{
if(run->next)
{
if(ready->next)
{
ins(block,run->next);
ins(run,ready->next);
del(run);
del(ready);
}
else
{
ins(block,run->next);
ins(run,block->next);
del(block);
del(run);
}
}
}
else if(i==4)
{
if(block->next)
{
ins(ready,block->next);
del(block);
}
}
else
break;
dis();
cout<<"chose:\t1:ready->run\t2:run->ready\t3:run->block\t4:block->ready\n";
}
return 0;
}