构造与析构一道题

#include<stdio.h>
#include<string>

class Value
{
public:
    Value(int nVal) {
        m_nVal=nVal;
        printf("Call Value::Value(int nValue)/n");
    }
    ~Value() {
        printf("Call Value::~Value()/n");
    }
    Value& operator=(int nVal)
    {
       m_nVal=nVal;
       printf("Call Value::operator=/n");
       return *this;
    }
    void Dump() {
        printf("Value::m_nVal=%d/n",m_nVal);
    }
protected:
    int m_nVal;
};
class Base
{
public:
    Base() {
        Init();
    }
    virtual ~Base() {
        Release();
    }
    virtual void Init() {
        printf("Call Base::Init()/n");
    }
    virtual void Release() {
        printf("Call Base::Release()/n");
    }
    virtual void Dump() {
        printf("Call Base::Dump()/n");
    }
};

class Derive:public Base
{
public:
    Derive() {
        printf("Call Derive::Derive()/n");
    }
    ~Derive() {
        printf("Call Derive::~Derive()/n");
    }
    virtual void Init() {
        m_Val=2;
        printf("Call Derive::Init()/n");
    }
    virtual void Release() {
        printf("Call Derive::Release()/n");
    }
    virtual void Dump() {
        m_Val.Dump();
    }
protected:
    static Value m_Val;
};

Value Derive::m_Val=0;

void DestroyObj(Base* pOb)
{
    pOb->Dump();
    delete pOb;
}

void main()
{
    Derive *pOb = new Derive;
    DestroyObj(pOb);
}

输出：

    Call Value::Value(int nValue)    //静态变量构造
    Call Base::Init()                //基类构造
    Call Derive::Derive()            //派生类构造
    Value::m_nVal=0                  //多态
    Call Derive::~Derive()           //派生类析构
    Call Base::Release()             //基类析构
    Call Value::~Value()             //静态变量析构