下面程序中A是抽象类，其输出是什么?
2024-07-27C+ + 程序设计(04737)
下面程序中A是抽象类，其输出是什么? 
【正确答案】：This is class A printing. This is class A printing.
【正确答案】：This is class A printing. This is class A printing.