答:
可以。将析构函数声明为虚析构函数,当基类指针指向派生类对象的时候,这时候通过基类指针来释放派生类对象,虚析构函数就显得特别有用。
例如下面程序:
# include<iostream>
using namespace std;
class A
{
public:
A() { cout << "construct A" << endl; }
~A() { cout << "delete A" << endl; }
};
class B :public A
{
public:
B() { cout << "construct B" << endl; }
~B()
{
cout << "delete B" << endl;
}
};
int main()
{
A* a = new B;
delete a;
return 0;
}
程序运行结果如下图所示:
可以发现,B的析构函数没有调用,这时如果B里面有申请的空间,就得不到释放。
如果我们修改程序如下:
# include<iostream>
using namespace std;
class A
{
public:
A() { cout << "construct A" << endl; }
virtual ~A() { cout << "delete A" << endl; }
};
class B :public A
{
public:
B() { cout << "construct B" << endl; }
~B()
{
cout << "delete B" << endl;
}
};
int main()
{
A* a = new B;
delete a;
return 0;
}
可以发现派类得析构函数已正常调用。