Problem A: 还会用继承吗？

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Description

定义一个Base类，包括1个int类型的属性，以及满足输出格式要求的构造函数、拷贝构造函数和析构函数。

定义Base类的子类Derived，包括1个int类型的属性，以及满足输出格式要求的构造函数、拷贝构造函数和析构函数。

Input

第1行N>0表示测试用例个数。

每个测试包括2个int类型的整数。

Output

见样例。

Sample Input

110 20

Sample Output

Base = 10 is created.Base = 10 is copied.Base = 10 is created.Derived = 20 is created.Base = 10 is copied.Derived = 20 is copied.Derived = 20 is erased.Base = 10 is erased.Derived = 20 is erased.Base = 10 is erased.Base = 10 is erased.Base = 10 is erased.

#include <iostream>using namespace std;class Base{  public:      int n;      Base(int a):n(a){cout<<"Base = "<<n<<" is created."<<endl;}      Base(Base&A):n(A.n){cout<<"Base = "<<n<<" is copied."<<endl;}      ~Base(){cout<<"Base = "<<n<<" is erased."<<endl;}};class Derived:public Base{  private:      int m;  public:      Derived(int a,int b):Base(a),m(b){         cout<<"Derived = "<<m<<" is created."<<endl;      }      Derived(Derived &A):Base(A),m(A.m){         cout<<"Derived = "<<m<<" is copied."<<endl;      }      ~Derived(){         cout<<"Derived = "<<m<<" is erased."<<endl;      }};int main(){    int cases, data1, data2;    cin>>cases;    for (int i = 0; i < cases; i++)    {        cin>>data1>>data2;        Base base1(data1), base2(base1);         Derived derived1(data1, data2), derived2(derived1);    }}

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