【C/C++】C++虚析构函数的作用

1、作用

为了在实现多态的时候不造成内存泄露,

如果基类析构函数前不加vitual，派生类对象被销毁后，只会调用基类的析构函数，而不会去调用派生类的析构函数。

2、对于正常的函数，如果基类中声明为virtual，则派生类可以不用再写virtual

// CPPTest.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
class Base
{
public:
Base(){}
virtual ~Base()
{
printf("Base Destructor!/n");
}
virtual void Func()
{
printf("Base Func!/n");
}
private:
int m_iData;
};
class Derived : public Base
{
public:
Derived(){}
~Derived()
{
printf("Derived Destructor!/n");
}
void Func()
{
printf("Derived Func!/n");
}
};
class Derived2 : public Derived
{
public:
Derived2(){}
~Derived2()
{
printf("Derived2 Destructor!/n");
}
void Func()
{
printf("Derived2 Func!/n");
}
};

int main(int argc, char* argv[])
{
Base *pb = new Base;
pb->Func();
Base *pd = new Derived;
pd->Func();
Base *pd2 = new Derived2;
pd2->Func();
delete pb;
delete pd;
delete pd2;
return 0;
}

结果：

Base Func!

Derived Func!

Derived2 Func!

Base Destructor!

Derived Destructor!

Base Destructor!

Derived2 Destructor!

Derived Destructor!

Base Destructor!