關于繼承的問題

水清苓

各位:以下代碼何錯之有啊??
爲什麽老提示錯誤???


#include<iostream>
class base
{
int m1() { return 30; }
public:
virtual int m2() { return 40; }
virtual ~base() { }
};
class derived : public base
{
public:
int m2() { return 50; }
};
void main()
{
base *p_b = new base();
derived *p_d = new derived();
cout << "b->m3(): " << b->m3() << endl;
cout << "d->m3(): " << d->m3() << endl;
delete b;
b =d;
cout << "b_d->m3(): " << b->m3() <<endl;
delete d;
}

THX!!!!

深水海狗

还没看你怎么写的，我想问问：

b,d,m3()这些似乎都没声明！

叛逆ぁ太上皇

错误真不是一般的多
以下打红字的就是你的错误了~~~

#include<iostream>
using namespace std; //少了名字空间
class base
{
int m1() { return 30; }
public:
virtual int m3() { return 40; } //你定义m2,却在主函数中使用了m3
virtual ~base() { }
};
class derived : public base
{
public:
int m3() { return 50; } //同上
};
void main()
{
base *p_b = new base(); //定义指针名称为 p_b,但在主函数中使用了 b;
derived *p_d = new derived(); //同上
cout << "b->m3(): " << p_b->m3() << endl;
cout << "d->m3(): " << p_d->m3() << endl;
delete p_b;
p_b =p_d;
cout << "b_d->m3(): " << p_b->m3() <<endl;
delete p_d;
}

半个灵魂

原來....
3Q拉!!!!!!!