有关C语言时间轮转算法

//大神帮看看哪有错，怎么改，谢谢了！
#include
#include
#define NULL 0
int s=1;
struct PCB{
char p_name[20];
int arrivetime;
int p_needTime;
int p_runTime;
char p_state;
struct PCB* next;
};
void RoundRobin();
char Choice();

int main()
{

char choice = Choice();
switch(choice)
{

    case '1':
        system("cls");
        RoundRobin();
        break;
    case '2':
        return 0;
        break;
    default:
        break;
}
system("pause");
return 0;

}
char Choice()
{
printf("\n\n");
printf(" ********************************************* \n");
printf(" 进程调度演示\n");
printf(" ********************************************* \n\n\n");

printf(" 1.演示轮转法算法.\n");
printf(" 2.退出程序.\n\n");
printf(" 选择进程调度方法:");

char ch = getchar();
return ch;
system("cls");
}

//轮转算法
void RoundRobin()
{
int N,TIME;
printf("请指明时间片大小:");
scanf("%d",&N);
int n;
struct PCB processes, *pt,*min,*q,*de,*z,*x;
processes = pt = min=q=de=(struct PCB)malloc(sizeof(struct PCB));

struct PCB p,*ptem;
ptem=p=z=x=(struct PCB)malloc(sizeof(struct PCB));
z=pt;
x=q;
printf("请输入需要运行进程数：");
scanf("%d",&n);

for (int i = 0; i<n; ++i)//输入队列
{ 
    printf("输入进程名：");
    scanf("%s", &p->p_name);
    printf("输入进程运行时间：");
    scanf("%d", &p->p_needTime);
    printf("请输入到达时间：");
    scanf("%d,&p->arrivetime");
    p->p_runTime = p->p_needTime;
    p->p_state = 'W';
    z->next=p;
    z=z->next;
    printf("\n");
}
z->next=NULL;
z=pt->next;

for(i=1;i<n;i++)//排成有序队列
{
    min=z;
    while(z->next!=NULL)//选出输入队列最早到达的·
    {
        if(min->arrivetime>z->next->arrivetime)
        {
            min=z->next;
            p=z;
        }
        z=z->next;
    }
    z=p;
    z->next=min->next;
    x->next=min;//插入有序队列
    x=x->next;
}
z=pt->next;
x->next=z;
x=x->next;
x->next=NULL;
x=q->next;
q->next=x->next;
processes->next=x;
de=processes->next;
de->next=NULL;
TIME=x->arrivetime;
int cases = 0;
while (s)//开始运算队列
{
    if(de==NULL)
    {
        printf("进程全部结束！");
        s=0;
        continue;
    }
    ++cases; 
    printf("第%d轮: \n", cases);
    printf("**** 当前正在运行的进程是：%s\n", de->p_name);
    de->p_state = 'R';
    if(de->p_runTime<=N)
    {
        TIME=TIME+de->p_runTime;
        de->p_state='f';
        de->p_runTime=0;
    }
    else 
    {
        TIME=TIME+N;
        de->p_runTime-=N;
    }

    printf("进程名  状态  共需时间  还需时间\n");
    printf("%s\t%c\t%d\t%d\t\n\n", de->p_name, de->p_state, de->p_needTime, de->p_runTime);

    printf("**** 当前就绪状态的队列为：\n\n");       
    while (de->next != NULL)
    {
        de=de->next;
        printf("进程名   状态  共需时间   还需时间\n");
        printf("%s\t%c\t%d\t%d\t\n\n", de->p_name, de->p_state, de->p_needTime, de->p_runTime);
    }
    ptem=de;//最后一个进程用ptem表示
    de=processes->next;
    if(de->p_state =='f')//删除状态为f的进程
    {
        processes->next=de->next;
        de=processes->next;
    }
    else//将执行过的进程插到队尾
    {
        de->p_state='w';  
        processes->next=de->next;
        ptem->next=de;
        ptem=ptem->next;
        ptem->next=NULL;
    }
    while(q->next!=NULL&&q->next->arrivetime<TIME)//从序列队列中找出适合的插到执行队列
    {
            x=q->next;
            q->next=x->next;
            ptem->next=x;
            ptem=ptem->next;
            ptem->next=NULL;
    }

    while(de==NULL&&q->next!=NULL)
    {
        x=q->next;
        q->next=x->next;
        ptem->next=x;
        ptem=ptem->next;
        ptem->next=NULL;
    }
    de=processes->next;
}

}

http://blog.csdn.net/eaglewood2005/article/details/4377883