四、寫出下面 C++程式的執行結果。（執行結果共有五列輸出，請標明每列輸出的列號與內容）（20 分） #include class A { private: static int count; public: A() {++count; }; virtual void methodOne() { cout << "A's methodOne" << endl; } void methodTwo() { cout << "A's methodTwo" << endl; } static void numberOfinstanceOfA() { cout<< “# of A’s instances:” << count << endl; } ~A() { --count; } }; class B : public A{ public: B() {}; virtual void methodOne() { cout << "B's methodOne" << endl; } void methodTwo() { cout << "B's methodTwo" << endl; } }; int A::count = 0; void main() { A::numberOfinstanceOfA(); A *ptr = new B(); ptr->methodOne(); ptr->methodTwo(); A::numberOfinstanceOfA(); delete ptr; A::numberOfinstanceOfA(); }