#include
int main()
{
char c;
int cnt=0;
printf("请输入一行字符(回车结束):\n");
while((c=getchar())!='\n')
{
if(c>='a'&&c<='z'||c>='A'&&c<='Z'||c>='0'&&c<='9')
cnt++;
else
break;
}
printf("%s法用户名!\n",c=='\n'&&cnt>=6&&cnt<=16?"合":"非");
return 0;
}