Line *Line_ptr; //声明Line类的对象指针变量Line_ptr;
Line l1; //声明Line类实例对象L1
Line_ptr=&L1; //取L1的地址赋值给Line_ptr;
int getlength()
{
return length;
}
cout<<Line_ptr->getlength()<<endl;
cout<<L1.getlength()<<endl; //两者等价