在问个c++有关问题

在问个c++问题

C/C++ code

#include <iostream>using namespace std;class b{public:    b(){};    ~b(){};    virtual void setn(int m_){k=new int[m_];}    virtual void show(){cout<<k<<endl;}protected:    int *k;};class c:public b{public:    c(){};    ~c(){ delete d[];};    void setn(int m_);    void show();private:    int* d;};void c::setn(int m_){    d = new int[m_];    b::setn(m_);}void c::show(){    cout<<k<<endl;    cout<<d<<endl;}int main(){        c z;    z.setn(7);    z.show();    return 0;}