2_processpcb.cpp

来自「实现PCB的模似程序,已经通过C++编译」· C++ 代码 · 共 73 行

#include <malloc.h>
#include <stdio.h>
#include <string.h>
#define NULL 0
typedef struct processpcb
 { int id;/*进程控制块编号*/
   struct processpcb *next;
 }node;
 int n; 
 node *creat(void)   /*建立进程控制块队列表*/
 { node *head,*p1,*p2;
   n=0;
   printf("Input processpcb table:ID\n");
   p1=p2=(node *)malloc(sizeof(node));
   scanf("%d",&p1->id);
   head=NULL;
   while (p1->id>0)
    {n=n+1;
     if (n==1) head=p1;
     else p2->next=p1;
     p2=p1;
     p1=(node *) malloc (sizeof(node));
     scanf("%d",&p1->id);
    }
   p2->next=NULL;
   return(head);
 }
node *queue(node *head,int pcbin,int pcbout)
  {node *p,*q;
   p=head;q->id=pcbin;q->next=NULL;
   if(!head)
      head=q;
   else
    {while(p->next)
     p=p->next;
      p->next=q;
      p=q;
    }
    p=head;
   if(!head)
     printf("not found!");
   else
    {while(p&&p->id!=pcbout)
       {q=p;p=p->next;}
     if(p)
       {q->next=p->next;printf("found!");}
     else
       printf("not found!");
    }
  return(head);
 }
 void print (node *head)  /*输出链表*/
 { node *p;
   p=head;
   if(head !=NULL)
     do{printf("%d\t",p->id); p=p->next;}
    while(p!=NULL);
 }
void main()
{node *p,*q;
 int pcbin,pcbout;
 p=creat();
 printf("\ninit_processpcb queue is:\n");
 print(p);
 printf("\nappend a processpcb\n");
 scanf("%d",&pcbin);
 printf("\ndel a processpcb\n");
 scanf("%d",&pcbout);
 p=queue(p,pcbin,pcbout);
 printf("\n new processpcb queue is:\n");
 print(p);
}