求解，代码没错，却提示错误！

#include<iostream>
using namespace std;
class point
{
public:
point(int i=0,int j=0){x0=i;y0=j;}
virtual void set()=0;
virtual void draw()=0;
protected:
int x0,y0;
};
class lime:public point
{
public:

    line(int i=0,int j=0,int m=0,int n=0):point(i,j)
    {
    x1=m;y1=n;
    }
    void set(){cout<<"line::set()called.\n";}
    void draw(){cout<<"line::draw()callede.\n";}
protected:
    int x1,y1;

};
class ellipse:public point
{
public:
    ellipse(int i=0,int j=0,int p=0,int q=0):point(i,j))
    {
    x2=p;
    y2=q;
    }
};
void drawobj(point *p)
{
p->draw();
}
void main()
{
line *lineobj=new line;
ellipse  *elliobj=new ellipse;
drawobj(lineobj);
drawobj(elliobj);
cout<<endl;
setobj(lineobj);
setobj(elliobj);
cout<<"\nRedraw the...\n";
drawobj(lineobj);
cout<<"\nRedraw the object...\n";
drawobj(lineobj);
drawobj(elliobj);
}