C++虚析构函数

//本例演示析构函数需要被定义成虚函数的情况，注意构造函数是不可以被定义成虚函数的
#include<iostream>
using namespace std;
class Base{
public:
	~Base();				//virtual ~Base();	
};
Base::~Base(){
	cout<<"Base destructor"<<endl;
}

class Derived : public Base{
private:
	int *p;
public:
	Derived();
	~Derived();		//virtual ~Derived();
};
Derived::Derived(){
	p = new int(0);
}
Derived::~Derived(){				
	cout<<"Derived destructor"<<endl;			
}

void fun(Base *b){
	delete b;
}

int main(){
	Base *b = new Derived();
	fun(b);				//由于会直接调用基类，所以在派生类中分配的空间不会被释放掉，造成内存泄露
					//解决方法是：将基类和派生类的析构函数声明为虚函数（即每行注释的代码）
	system("pause");
	return 0;
}