基于优先数进程调度算法

  1 #include <stdio.h>
  2 #include <stdlib.h>
  3 typedef struct  node//一个进程的结构
  4 {
  5     int pid;   //进程ID号
  6     int priority;  //进程优先数
  7     int time;     //进程分配的时间片
  8     char state;   //进程的状态
  9     struct node * next;
 10 }pcb;
 11 
 12 
 13 pcb * p;
 14 pcb * creat();  //进程的创建
 15 int output();   //输出队列信息
 16 pcb * insert(pcb * head,pcb * p); //进程p的插入
 17 pcb * del(pcb * head,pcb * p);
 18 int priority(pcb * head);
 19 int s=0;
 20 int a[10000];
 21 
 22 
 23 pcb * creat()   //基于进程链表的创建
 24 {
 25     pcb * p1,* head;
 26     int i,num;
 27     head=NULL;
 28     printf("进程个数:\n");
 29     scanf("%d",&num);
 30     for(i=0;i<num;i++)
 31     {
 32         printf("请输入第%d个进程的信息:\n",i+1);
 33         p1=(pcb *)malloc(sizeof(pcb));
 34         printf("输入进程优先数:\n");
 35         scanf("%d",&p1->priority);
 36         printf("输入进程分配的时间:\n");
 37         scanf("%d",&p1->time);
 38         p1->pid=i+1;
 39         printf("\n");
 40         p1->state=‘W‘;
 41         head=insert(head,p1);
 42     }
 43     return head;
 44 }
 45 
 46 int output(pcb * head)     //输出链表信息
 47 {
 48     pcb * p;
 49     p=head;
 50     do
 51     {
 52         printf("%d  %d  %d  %c\n",p->pid,p->priority,p->time,p->state);
 53         p=p->next;
 54     }
 55     while(NULL!=p);
 56     return 0;
 57 }
 58 
 59 pcb * insert(pcb * head,pcb * p)  //将p按照优先级插入链表
 60 {
 61     pcb * p0,* p1,* p2;
 62     p1=head;
 63     p0=p;
 64     if(head==NULL)
 65     {
 66         head=p0;
 67         p0->next=NULL;
 68     }
 69     else
 70     {
 71         while((p1->priority>=p0->priority) && (p1->next!=NULL))   //寻找位置
 72         {
 73             p2=p1;
 74             p1=p1->next;
 75         }
 76         if(p0->priority>p1->priority)  //如果p0大于p1的优先级,找到存放的位置
 77         {
 78             if(head==p1)   //并且p1正在运行,此时链表为p1,NULL
 79             {
 80                 head=p0;
 81             }
 82             else
 83             {
 84                 p2->next=p0;
 85                 p0->next=p1;
 86             }
 87         }
 88         else              //因为p1->next=NULL跳出
 89         {
 90             p1->next=p0;
 91             p0->next=NULL;
 92         }
 93     }
 94     return head;
 95 }
 96 
 97 pcb * del(pcb * head,pcb * p) //进程p的删除
 98 {
 99     p->state=‘F‘;
100     printf("进程%d已经DELETE\n",p->pid);
101     printf("\n");
102     return head;
103 }
104 
105 int priority(pcb * head)  //进程的调度
106 {
107     char flag;
108     pcb * p,* rp;
109     p=head;
110     while(NULL!=p)
111     {
112         rp=p;
113         p=p->next;
114         do
115         {
116             flag=‘y‘;
117             printf("进程%drunning\n",rp->pid);
118             rp->state=‘R‘;
119             rp->priority=rp->priority-3;
120             rp->time--;
121             a[s++]=rp->pid;
122             output(rp);
123             rp->state=‘W‘;
124             printf("\n");
125             if(0==rp->time)
126                 p=del(p,rp);
127             else
128             {
129                  if((p==NULL) || (rp->priority>=p->priority))
130                      flag=‘n‘;
131                  else
132                  {
133                      p=insert(p,rp);
134                      printf("当前链表信息\n");
135                      output(p);
136                      printf("\n");
137                  }
138             }
139         }
140         while(flag==‘n‘);
141     }
142     return 0;
143 }
144 
145 int main()
146 {
147     int i;
148     pcb * head=NULL;
149     printf("please input data!\n");
150     head=creat();
151     printf("链表信息\n");
152     output(head);
153     printf("\n");
154     printf("begin running!\n");
155     printf("\n");
156     priority(head);
157     for(i=0;i<s;i++)
158     {
159         printf("%d",a[i]);
160         if(i!=s-1)
161             printf("-->");
162     }
163     printf("\n");
164     return 0;
165 }