c++ 虚析构函数[避免内存泄漏]

#include <iostream>
using namespace std;
#include <string>
//////////////////////////// 
class Base {
public:

#if  0
    virtual ~Base();// in Child::~Child()    in Base::~Base()
#else
     ~Base();        // in Base::~Base() 存在内存泄漏的危险
#endif
};

Base::~Base()
{
    cout<<"in Base::~Base()"<<endl;
}
////////////////////////////

class Child: public Base {
public:
    ~Child();
};

Child::~Child()
{
    cout<<"in Child::~Child()"<<endl;
}

int demo()
{
    Base *pc = new Child;
    cout<<"-----------"<<endl;
    delete pc;
    cout<<"-----------"<<endl;
    return 0 ;
}

int main() {
    demo();
    while(1);
    return 0;
}