jcdd2.c

进程是操作系统最重要的概念之一

#include<stdio.h>
#include<string.h> 
#include<malloc.h> 
#define NULL 0 
#define LEN sizeof(struct pcb) 
struct pcb 
{ int pid; 
struct pcb *next; 
int time; 
int priority; 
char status; 
}; 
int n,m; 
struct pcb *head,*runpcb; 
main() 
{ struct pcb *pcbi; 
char str; 
struct pcb *cshlist(); 
void insertproc(struct pcb *insproc); 
void pintlist(struct pcb *L); 
void execproc(); 
void delproc(); 
m=0; 
head=cshlist(); 
printf("first linelist is:\n"); 
pintlist(head); 
while(head!=NULL) 
{ scanf("%c",&str); 
runpcb=head; 
head=runpcb->next; 
runpcb->status='Z'; 
printf("output linelist is:\n"); 
printf("%d\n",m); 
printf("%2d %5d %5d %3c\n",runpcb->pid,runpcb->time,runpcb->priority,runpcb->status); 
pintlist(head); 
printf("\n"); 
printf("\n"); 
execproc(); 
m=m+1; 
if(runpcb->time==0) 
delproc(); 
else insertproc(runpcb); 
} 

} 
void pintlist(struct pcb *L) 
{ 
struct pcb *p; 
int i; 
p=L; 
if(L!=NULL) 
do 
{ printf("%2d %5d %5d %3c\n",p->pid,p->time,p->priority,p->status); 
p=p->next; 
}while (p!=NULL); 
} 

struct pcb *cshlist() 
{ 
struct pcb *ql; 

n=0; 
ql=(struct pcb *)malloc(LEN); 
ql->pid=n+1; 
ql->status='R'; 
printf("enter time and priority:\n"); 
scanf("%ld,%d",&ql->time,&ql->priority); 

head=NULL; 
while(ql->time!=0) 
{ 
n=n+1; 
insertproc(ql); 
ql=(struct pcb *)malloc(LEN); 
printf("enter time and priority:\n");
ql->pid=n+1; 
ql->status='R'; 
} 
return(head); 
} 
void insertproc(struct pcb *insproc) 
{ 
struct pcb *p0,*p1,*p2; 
int pri; 
p1=head; 
p0=insproc; 
if(head==NULL) 
{ 
head=p0; 
p0->next=NULL; 
} 
else 
{ 
pri=p0->priority; 
if(p1->priority<=pri) 
{ 
p0->next=head; 
head=insproc; 
} 
else 
{ 
while((p1->next!=NULL)&&(p1->priority>pri)) 
{ p2=p1; 
p1=p1->next; 
} 
if((p1->next!=NULL)||(p1->priority<=pri)) 
{ 
p2->next=p0; 
p0->next=p1; 
} 
else 
{ 
p1->next=p0; 
p0->next=NULL; 
} 
} 
} 
} 
void execproc() 
{ 
runpcb->time=runpcb->time-1; 
runpcb->priority=runpcb->priority-1; 
} 
void delproc() 
{ 
struct pcb *p; 
p=runpcb; 
p->status='E'; 
printf("process P"); 
printf("%d",p->pid); 
printf(" is finish\n"); 
printf("\n"); 
free(runpcb); 
}