一道关于C++继承类的面试题

集中写几个关于类继承语法的典型题目
1,

#include <iostream>
using namespace std;

class Base
{
    int i;
public:
    static int s;
    Base():i(0)
    {
        cout<<"Base:Construct"<<endl;
        s++;
    }
    static void sFun()
    {
        cout<<s<<endl;;
    }
    void f(float f)
    {
        cout<<"Base:f()"<<endl;
    }
    void g(float f)
    {
        cout<<"Base:g(float)"<<endl;
    }
};
int Base::s=0;

class Derived: public Base
{
    int j;
public:
    //基类构造函数先执行.
    Derived():j(0)
    {
        cout<<"Derived:Construct"<<endl;
        s++;
    }
    void f(float f)
    {
        cout<<"Derived:f()"<<endl;
    }
    void g(int f)
    {
        cout<<"Derived:g(int)"<<endl;
    }
};


int main()
{

    Base *pB;
    Base *pD;
    Derived d;
    pD=&d;
    pD->sFun();
    Base b;
    pB=&b;
    pB->sFun();

    //全是执行Base
    pB->f(3.14f);
    pD->f(3.14f);

    b.g(3.14f);
    d.g(3.14f);
    return 0;
}

2,

#include <iostream>
using namespace std;

class B
{
public:
    B()
    {
        cout<<"default constructor"<<endl;
    }
    ~B()
    {
        cout<<"destructed"<<endl;
    }
    B(int i):data(i)    //B(int) works as a converter ( int -> instance of  B)
    {
        cout<<"constructed by parameter " << data <<endl;
    }
private:
    int data;
};

B Play( B b)
{
    return b ;
}


int main()
{
    //case1:
    //析构三次:
    //默认,参数构造,返回复制
    B t1;
    t1 = Play(5);
    //case2:
    //析构两次:
    //参数构造,返回复制
    B t2= Play(5);
    return 0;
}