求助各位大佬！操作系统——非抢占式的优先级调度算法

[qq_37925974]

各位大佬！有木有人知道如何利用指针实现非抢占式的优先级调度算法啊？就是利用下面的时间片轮转调度算法代码修改成实现非抢占式的优先级调度算法功能的代码。我就是不太会用指针诶，用数组的话，这个的代码我是写出来了，可是它要求要用下面的代码修改成实现非抢占式的优先级调度算法功能的代码，我就有点懵了，操作了很久，就是不能完全对，想来求助吧里大佬，看看有谁能帮我看看的
这儿下面就是那个时间片轮转调度算法代码的main.cpp里的内容：
#define N 20
#include <stdio.h>
#include <conio.h>
typedef struct pcb /*进程控制块定义*/
{
char pname[N]; /*进程名*/
int runtime; /*运行时间*/
int arrivetime; /*到达时间*/
char state; /*进程状态*/
struct pcb *next; /*链接指针*/
}PCB;
PCB head_input;
PCB head_run;
PCB *pcb_input;
static char R='r',C='c';
unsigned long current; /*记录系统当前时间的变量*/
void inputprocess(); /*建立进程函数*/
int readyprocess(); /*建立就绪队列函数*/
int readydata(); /*判断进程是否就绪函数*/
int runprocess(); /*运行进程函数*/
FILE *f;
/*定义建立就绪队列函数*/
int readyprocess()
{
while(1)
{
if(readydata()==0)/*判断是否有就绪进程入队*/
return 1;
else
runprocess(); /*运行进程*/
}
}
/*定义判断就绪队列是否有进程*/
int readydata()
{
if(head_input.next==NULL)
{
if(head_run.next==NULL)
return 0;
else
return 1;
}


PCB *p1,*p2,*p3;
p1=head_run.next;
p2=&head_run;
while(p1!=NULL)
{ p2=p1; p1=p2->next; }
p1=p2;
p3=head_input.next;
p2=&head_input;
while(p3!=NULL)
{
if(((unsigned long)p3->arrivetime<=current)&&(p3->state==R))
{
printf("Time slice is%d(time%4d);Process %s start.\n",
current,(current+500)/1000,p3->pname);
fprintf(f,"Time slice is%8d(time%4d);Process%s start.＼n",
current,(current+500)/1000,p3->pname);
p2->next=p3->next;
p3->next=p1->next;
p1->next=p3;
p3=p2;//???不应该是p3=p2->next???
}
p2=p3;
p3=p3->next;
}
return 1;
}

int runprocess() /*运行进程*/
{
PCB *p1,*p2;
if(head_run.next==NULL)
{
current++;
return 1;
}
else
{
p1=head_run.next;
p2=&head_run;
while(p1!=NULL)
{
p1->runtime--;
current++;
if(p1->runtime<=0)
{
printf("Time slice is%8d time%4d;Process%s end．\n",current,
(current+500)/1000,p1->pname);
fprintf(f,"Time slice is%8d time%4d;Process%s end.\n",current,
(current+500)/1000,p1->pname);
p1->state=C;
p2->next= p1->next;
delete p1;
p1=NULL;
}
else
{
p2=p1;
p1=p2->next;
}
}
return 1;
}
}
/*定义建立进程函数*/
void inputprocess()
{
PCB *p1,*p2;
int num;
/*要建立的进程数*/
unsigned long max=0;
printf("How many processes do you want to run：");
fprintf(f,"How many processes do you want to run：");
scanf("%d",&num);
fprintf(f,"%d\n",&num);
p1=&head_input;
p2=p1;
p1->next=new PCB;
p1=p1->next;
for(int i=0;i<num;i++)
{
printf("No．%3d process input pname：",i+1);
fprintf(f,"No．%3d process input pname：",i+1);
scanf("%s",p1->pname);
fprintf(f,"%s\n",p1->pname);
printf(" runtime：");
fprintf(f," runtime：");
scanf("%d",&(p1->runtime));
fprintf(f,"%d\n",&(p1->runtime));
printf(" arrivetime：");
fprintf(f," arrivetime：");
scanf("%d",&(p1->arrivetime));
fprintf(f,"%d\n",&(p1->arrivetime));
p1->runtime=(p1->runtime)*1000;
p1->arrivetime=(p1->arrivetime)*1000;
p1->state=R;
if((unsigned long)(p1->arrivetime)>max)
max=p1->arrivetime;
p1->next=new PCB;
p2=p1;
p1=p1->next;
}
delete p1;
p1=NULL;
p2->next=NULL;
}
/*一一定义建立进程函数*/
void inputprocess1()
{
PCB *p1,*p2;
int num; /*要建立的进程数*/
unsigned long max=0;
printf("How many processes do you want to run：");
fprintf(f,"How many processes do you want to run：");
scanf("%d",&num);
fprintf(f,"%d\n",&num);
pcb_input=new PCB;
p1=pcb_input;
for(int i=0;i<num;i++)
{
printf("No．%3d process input pname：",i+1);
fprintf(f,"No．%3d process input pname：",i+1);
scanf("%s",p1->pname);
fprintf(f,"%s\n",p1->pname);
printf(" runtime：");
fprintf(f," runtime：");
scanf("%d",&(p1->runtime));
fprintf(f,"%d\n",&(p1->runtime));
printf(" arrivetime：");
fprintf(f," arrivetime：");
scanf("%d,",&(p1->arrivetime));
fprintf(f,"%d\n",&(p1->arrivetime));
// p1->runtime=(p1->runtime)：
// p1->arrivetime=(p1->arrivetime);
p1->runtime=(p1->runtime)*1000;
p1->arrivetime=(p1->arrivetime)*1000;
p1->state=R;
if(i!=num-1)
{ p1->next=new PCB; p1=p1->next;}
else
{ p1->next=pcb_input; }
}
p1=pcb_input;
while(p1->next!=pcb_input)
{
printf("Process name is%s\n",p1->pname);
fprintf(f,"process name is%s\n",p1->pname);
p1=p1->next;
}
printf("Proeess name is%s\n",p1->pname);
fprintf(f,"process name is%s\n",p1->pname);
}

void runprocessl() /*定义运行进程函数*/
{
pcb *pre,*cur;
if(pcb_input==NULL)
return ;
else
{
cur=pcb_input;
pre=cur->next;
while(pre->next!=cur) // find the last node in the list
{ pre=pre->next; }
while(cur->runtime>=0||(cur->next!=cur))
// while(1)
//if p1->next!=p1,it means that there are more than one pcb jobs
//if p1->next==p1 and p1->runtime<=O means a11 jobs have done;
{
if(current<(unsigned long)cur->arrivetime)
{ pre=cur; cur=cur->next;}
else
{
if( current==(unsigned long)cur->arrivetime)
{
printf("Time slice is %d(time&4d);Process %s start,\n",
current,(current+500)/1000,cur->pname);
fprintf(f,"Time slice is %8d(time%4d);Process %s start,\n",
current,(current+500)/1000,cur->pname);
}
cur->runtime--;
if(cur->runtime<0) //means the job have ended．
{
printf("Time slice is %8d time %4d;Process %s end．\n",
current,(current+500)/1000,cur->pname);
fprintf(f,"Time slice is %8d time %4d：Process %s end．\n",
current,(current+500)/1000,cur->pname);
if(cur==cur->next) //delete the last job then break;
{
delete cur;
cur=NULL;
//break;
return;
}
else
{
pre->next=cur->next;
pcb *tmp=cur;
delete tmp;
cur=pre->next;
}
}
else
{
cur->runtime--;
pre=cur;
cur=cur->next;
}
}
current++;
}}}
// To Do set one cycle link to solve the problem
int main()
{
f=fopen("result.txt","w");
printf("\ntime 1=1000 time slice\n");
fprintf(f,"\ntime 1=1000 time slice\n");
current=0;
inputprocess();
readyprocess();
// inputprocessl();
// runprocessl();
getch();
fclose(f);
}

[赵4老师]

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