dynamic_cast为什么可以做“变性手术”？
dynamic_cast为何可以将一个派生类指针转为另一个派生类指针并且调用另一个派生类的方法？
#include <iostream>
using namespace std;
class People
{
public:
People()
{
cout << "People constructed" << endl;
}
virtual void speak() = 0;
};
class Man:public People
{
public:
void speak()
{
cout << "A man speaks" << endl;
}
void fight()
{
cout << "A man fights" << endl;
}
};
class Woman:public People
{
private:
Man son;
public:
void speak()
{
cout << "A woman speaks" << endl;
}
void cook()
{
cout << "A woman cooks" << endl;
}
Man getSon()
{
cout << "A woman's son:" << endl;
return son;
}
};
///////////////////////////SubMain//////////////////////////////////
int main(int argc, char *argv[])
{
People *p = new Man();
p->speak();
Man *m = dynamic_cast<Man *>(p);
m->fight();
Man *m2 = (Man *)p;
m2->fight();
try
{
Woman *w = dynamic_cast<Woman *>(p);
// if (w != NULL)
// {
// w->cook();
// w->getSon().speak();
// }
// 如果不检查直接用的话，居然也可以
w->cook();
w->getSon().speak();
}
catch(bad_cast &e)
{
cout << "bad_cast exception" << endl;
}
delete p;
system("pause");
return 0;
}
///////////////////////////End Sub//////////////////////////////////
/************************************************************************/
/* output:
People constructed
A man speaks
A man fights
A man fights
A woman cooks
A woman's son:
A man speaks
*/
/************************************************************************/
class Woman:public People
{
private:
Man son;
int v;
public:
void speak()
{
cout << "A woman speaks" << endl;
}
void cook()
{
cout << "A woman cooks" << endl;
v=0;
}
Man getSon()
{
cout << "A woman's son:" << endl;
return son;
}
};
