如何解决这个小问题啊？很弱地问一声

Question

struct Item
{
float x;
float y;
COLORREF color;
Item *next;
};class List  
{
public:

void crea(CDC *pDC);

List();
virtual ~List();
private:
Item *list;//链表头
Item *tail;//链表尾
};
---------------------------------------------------------------------------------------
void List::crea(CDC *pDC)
{
    float x0,y0,r,t1,t2,e,temp1,temp2,temp3,temp4;
float t;
int i;
CPen pen;
pen.CreatePen(PS_SOLID,1,RGB(0,0XFF,0));
    CPen *oldpen=(CPen*)pDC->SelectObject(&pen);
for(i=1;i<NUM;i++)
{
Item *pt1,*pt2,*p=new Item;
x0=rand()%640;
         y0=rand()%480;
         r=20.0;
         t1=0.0;
         t2=PI;
              e=0.0001;
temp1=x0+r*cos(t1);//程序运行到这里就不动了？？？？？？？？
pt1->x=temp1;
temp2=y0+r*sin(t1);                                      ↑
pt1->y=temp2;                                             |
pt1->color=i;                                             |
         pDC->MoveTo(x0+r*cos(t1),y0+r*sin(t1));                   |
         for(t=t1;t<=t2;t+=e)                                      |
{                                                         |
  temp3=x0+r*cos(t);
  pt2->x=temp3;
  temp4=y0+r*sin(t);                                       |
  pt2->y=temp4;
  pt2->color=i;
  pDC->LineTo(x0+r*cos(t),y0+r*sin(t));                   |
  if(list==NULL)
{                                                 |
list=pt1;
p->next=pt2;                            |
p=pt2;
p->next=NULL;                           |
}
else                                              |
{
p->next=pt2;                             |
p=pt2->next;
p->next=NULL;                             | }                                                  |
                                                                              |
}
}                                                                    |

}                                                                             |
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我想在屏幕上画些随机的圆弧，并把圆弧上的点保存到链表里，代码如上，出问题的地方|如箭头所示，请教达人解决的方法

Answer 1

报告什么错呢？另外，MFC提供了链表CObList，不需要自己写的。