Question

VC＋＋编程

1设计一个Point类，这个类描述屏上一个点的位置，用它派生一个线段类Line.
2 为他们设计适当的成员函数，以便演示公有继承的赋值兼容性规则复制构造函数和析构函数的调用顺序．
3 重新使用这个实验
急用啊，还会提高奖赏的．．．．

Answer 1

#include<iostream>
using namespace std;
class point
{
public:
point()
{
x=0;
y=0;
cout<<"constructed point class!"<<endl;
}
~point()
{
cout<<"desstructed point class!"<<endl;
}
void setpoint(int a,int b)
{
x=a;
y=b;
cout<<"point::x:"<<x<<endl;
cout<<"point::y:"<<y<<endl;
}
virtual void dispoint()
{
cout<<"point::x:"<<x<<endl;
cout<<"point::y:"<<y<<endl;
}
private:
int x;
int y;
};

class line: public point
{
public:
line()
{
x=0;
y=0;
cout<<"constructed line class!"<<endl;
}
~line()
{
cout<<"desstructed line class!"<<endl;
}
void setpoint(int a,int b)
{
x=a;
y=b;
cout<<"line::x:"<<x<<endl;
cout<<"line::y:"<<y<<endl;
}
virtual void dispoint()
{
cout<<"line::x:"<<x<<endl;
cout<<"line::y:"<<y<<endl;
}
private:
int x;
int y;

};

int main()
{
point A;
point *p;
line B;
p=&A;
p->setpoint(2,3);
p->dispoint();
p=&B;
p->setpoint(4,7);
p->dispoint();
return 0;
}