运行时67行while(flag==1)出错，能力有限怎么改都不会，望大家帮帮忙

#include<stdio.h>
#include<malloc.h>
#include<string.h>
#include<time.h>
typedef struct seedoctor{
char data[100]; /*数据域*/

struct seedoctor *next;/*指针域 */
}seetype;/*键队列节点类型 */

typedef struct{
seetype *front,*rear;}
linkqueue;/*键队类型 */
#define null 0
/*登陆界面*/
void jiemian()
{
printf("\t*****************************\n");
printf("\t*****************************\n");
printf("\t*****************************\n");
printf("\t****   病人就医管理系统   ****\n");
printf("\t*****************************\n");
printf("\t*****************************\n");
printf("\t*****************************\n");
}
/*设置密码 */
void cipher()
{
int a,i;
a=123;
printf("\t请输入密码：");
scanf("\t%d",&a);
for(i=1;i<3;i++)
if(a!=123)
{printf("\t密码错误！请重新输入：");
scanf("\t%d",&a);}
if(a!=123)
{
printf("\t登录失败/n");
exit(0);}
printf("登陆成功\n");}
void welcome()
{
printf("\t*****************************\n");
printf("\t*****************************\n");
printf("\t*****************************\n");
printf("\t****   病人就医管理系统   ****\n");
printf("\t*****************************\n");
printf("\t*****************************\n");
printf("\t*****************************\n");
}
/*主要功能*/
void module()
{
printf("\t主要功能如下：\n");}
/*功能的实现*/
void seedoctor()
{
int sel,flag=1;
linkqueue *lq;
seetype *s;
char number[100];
lq=(linkqueue *)malloc(sizeof(linkqueue));
lq->front=(seetype *)malloc(sizeof(seetype));
lq->front->next=null;
lq->rear=lq->front;
while(flag==1)}
/*主要模块*/
{
printf("\t*******************************\n");
printf("\t*******************************\n");
printf("\t*********  1  2  3  4  ********\n");
printf("\t** 排队  就诊  查看排队  下班**\n");
printf("\t请选择：");
scanf("\t%d",&sel);
clrsr();
switch(sel)}
/*患者排队 */
case 1:
textbackground(11);
printf("\t********************\n");
printf("\t********************\n");
printf("\t输入患者病历号\n");
scanf("\t%s",number);
s=(seetype *)malloc(sizeof(seetype));
strcpy(s->data,number);
s->next=null;
lq->rear->next=s;
lq->rear==s;
break;
/*患者就诊 */
case 2：
if(lq->front=lq->rear)
printf("\t没有排队的患者\n");
eles
{
s=lq->front->next;
if(lq->rear==s)
lq->rear=lq->front;
printf("\t患者%s就诊\n",s->data);
lq->front->next=s->next;
free(s);}
break;
/*查看排队 */
case 3:
if(lq->front==lq->rear)
printf("\t没有排队的患者\n");
eles
{
s=lq->front->next;
printf("\t排队患者：\n");
while(s!=null)
{
printf("\t%s",s->data);
s=s->next;
}
printf("\n");
}
break;
/*下班*/
case 2:
if(lq->front!=lq->rear)
{printf("\t请排队的患者明天就诊\n");
flag=0;
break;}
}
}
/*退出系统*/
void end()
{
    printf("\t**************************\n");
    printf("\t**************************\n");
    printf("\t**************************\n");
    printf("\t 谢谢使用病人就医管理系统 \n");
     printf("\t**************************\n");
    printf("\t**************************\n");
    printf("\t**************************\n");
}
/*主函数 */
void main()
{
system("graftabl936");
clrscr();
textbackgroud(11);
textcolor(11);
jiemian();
cipher();
welcome();
seedoctor();
clrscr();
end()
}
long I,t;
for(i=ol;i<10000000l;i++)
{
syetem("cls");
t=time(null);
printf("%d%d%d\n");
printf(ctime(&t));
}}}

[local]1[/local]