我尝试创建一个工人类，但我得到了“纯虚方法”

I try to make an abstract class to parallelise some works. I would like to have something where I can put a lot of work and don't care about how it's done. But I have a strange bug, when I run it, I got a console output "pure virtual method called", but I don't have any problem when I compile it. C++ is intended to avoid that kind of call ? No ?I try to make an abstract class to parallelise