看病排队问题

#include <stdio.h>
#include <malloc.h>
#include <string.h>
typedef struct QNode 
{
    char data[10];
    struct QNode *next;
} QType;        /*链队结点类型*/
typedef struct 
{
    QType *front,*rear;
} LinkQueue;    /*链队类型*/
void SeeDoctor()
{
    int sel,flag=1;
    LinkQueue *lq;
    QType *s;
    char name[10];
    lq=(LinkQueue *)malloc(sizeof(LinkQueue));
    lq->front=(QType *)malloc(sizeof(QType));
    lq->front->next=NULL;
    lq->rear=lq->front;
    while (flag==1)     /*未下班时循环执行*/
    {
        printf("1:排队 2:看医生 3:查看排队 0:下班  请选择:");
        scanf("%d",&sel); 
        switch(sel) 
        {
        case 0:
            if (lq->front!=lq->rear)     /*队不空*/
                    printf("  >>请排队的患者明天就医\n");
            flag=0;
            break;
        case 1:
            printf("  >>输入患者姓名:");scanf("%s",name);
            s=(QType *)malloc(sizeof(QType));
            strcpy(s->data,name);s->next=NULL;
            lq->rear->next=s;lq->rear=s;
            break;
           case 2:    
            if (lq->front==lq->rear)    /*队空*/
                printf("  >>没有排队的患者\n");
            else 
            {
                s=lq->front->next;
                if (lq->rear==s)
                    lq->rear=lq->front;
                printf("  >>患者%s看医生\n",s->data);
                lq->front->next=s->next;
                free(s);
            }
            break;
           case 3:
            if (lq->front==lq->rear)    /*队空*/
                printf("  >>没有排列的患者\n");
            else 
            {    
                s=lq->front->next;
                printf("  >>排队患者:");
                while (s!=NULL) 
                {      
                    printf("%s ",s->data);
                    s=s->next;
                }
                printf("\n");
            }
            break;
        }
    }
}
void main()
{
    SeeDoctor();
}