Problem A: 還會用繼承嗎？

Description

定義一個Base類，包括1個int類型的屬性，以及滿足輸出格式要求的構造函數、拷貝構造函數和析構函數。

定義Base類的子類Derived，包括1個int類型的屬性， 以及滿足輸出格式要求的構造函數、拷貝構造函數和析構函數。

Input

第1行N>0表示測試用例個數。

每個測試包括2個int類型的整數。

Output

見樣例。

#include <iostream>

using namespace std;

class Base{
private:
    int x;
public:
    Base(int a) : x(a) {
        cout << "Base = " << x << " is created." << endl;
    }
    Base(const Base &b) {
        x = b.x;
        cout << "Base = " << x << " is copied." << endl;
    }
    ~Base() {
        cout << "Base = " << x << " is erased." << endl;
    }
};

class Derived : public Base {
private:
    int x;
public:
    Derived(int a, int b) : Base(a), x(b) {
        cout << "Derived = " << x << " is created." << endl;
    }
    Derived(const Derived &d) : Base(d) {
        x = d.x;
        cout << "Derived = " << x << " is copied." << endl;
    }
    ~Derived() {
        cout << "Derived = " << x << " 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);
    }
}