C++编程填空：构造与析构

描述

请完善程序，使得所有类型能够正确初始和消亡

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
using namespace std;
// 在此处补充你的代码
int main(){
    int n;
    cin >> n;
    for (int i = 1; i<=n; i++) {
        int x;
        cin >> x;
        if (x == 0) {
            A *a = new A();
            delete a;
        }else {
            A *a = new B();
            delete a;
        }
    }
    return 0;   
}

样例输入

3
1 0 1

样例输出

New A
New B
Delete B
Delete A
New A 
Delete A
New A
New B
Delete B
Delete A

http://cxsjsx.openjudge.cn/2018midexamcloze/8/

class A
{
public:
   A(){cout<<"New A"<<endl;}
   virtual ~A(){cout<<"Delete A"<<endl;}
};
class B:public A
{
public:
    B(){cout<<"New B"<<endl;}
    virtual ~B(){cout<<"Delete B"<<endl;}
};

class Clock
{
public:
Clock(int NewH, int NewM, int NewS); //构造函数
void SetTime(int NewH, int NewM, int NewS);
void ShowTime();
private:
int Hour, Minute, Second;
};
构造函数的实现：

    Clock::Clock(int NewH, int NewM, int NewS)
    {
             Hour=NewH;
             Minute=NewM;
             Second=NewS;
    }
    建立对象时构造函数的作用：

    int main()
    {
            Clock c(0,0,0); //隐含调用构造函数，将初始值作为实参。
            c.ShowTime();
            return 0;
    }