进程调度算法——优先级调度

算法流程

 

代码实现

/*
非抢占式优先级进程调度
*/
#include<stdio.h>
#include<stdlib.h>
typedef struct PCB
{
        int pid;
        int need_time;//进程运行所需时间
        int priority;//进程优先级
        char state;//进程状态
        struct PCB *next;
}*Queue,Q;
Queue createProcess(int n)
{
        Queue head,s,t;
        int time,i=0,j;
        head=(Queue)malloc(sizeof(Q));
        printf("请输入进程所需时间：");
        scanf("%d",&time);
        head->need_time=time;
        head->pid=1;
        printf("请输入进程优先级：");
        scanf("%d",&j);
        head->priority=j;
        head->state='R';
        t=head;
        for(i=1;i<n;i++)
        {
                s=(Queue)malloc(sizeof(Q));        
                printf("请输入进程所需时间：");
                scanf("%d",&time);
                s->need_time=time;
                s->pid=i+1;
                printf("请输入进程优先级：");
                scanf("%d",&j);
                s->state='R';
                s->priority=j;
                s->next=NULL;
                t->next=s;
                t=s;
        }
        return head;
}
void printProcess(Queue p)
{
        int i;
        Queue q;
        q=p;//->next
        printf("进程标识符\t运行时间\t优先级\t\t状态\n");
        while(q!=NULL)
        {
                printf("%d\t\t  %d  \t\t%d    \t\t%c\n",q->pid,q->need_time,q->priority,q->state);
                q=q->next;
        }
}
Queue sort(Queue head)//根据优先级进行冒泡排序
{
        Queue p,h,s,q,r,t;
        int m,pr;
        int pid;
        char st;
        h=head;
        p=head;//->next
        r=p;
        t=p;
        q=p->next;
        while(r!=NULL)
        {
                while(q!=NULL)
                {
                        if(p->priority<q->priority)
                        {
                                m=p->priority;
                                p->priority=q->priority;
                                q->priority=m;
                                pid=p->pid;
                                p->pid=q->pid;
                                q->pid=m;
                                pr=p->need_time;
                                p->need_time=q->need_time;
                                q->need_time=pr;
                                st=p->state;
                                p->state=q->state;
                                q->state=st;
                        }
                        p=q;
                        q=q->next;
                }
                r=r->next;
                p=t;
                q=p->next;
        }
        return head;
}
int main()
{
        Queue p=NULL,head=NULL,m=NULL,z=NULL;
        int j,time,x=0;
        char c,pid;
        printf("请输入进程数：");
        scanf("%d",&x);
        p=createProcess(x);
        head=p;//->next
        z=head;
        printf("*********************创建的进程********************\n");
        printProcess(head);
        printf("*********************进程调度过程******************\n");
        while(x>0)
        {
                sort(z);
                m=z;//->next
                m->state='E';
                if(m!=NULL)//head->next
                {
                        printProcess(head);
                }
                z=m->next;//->next
                //free(m);
                printf("进程%d已完成！\n",m->pid);
                x--;
        }
        printf("所有进程运行结束！\n");
        return 0;
}

效果