Robert Martin in 1995: Designing Object-Oriented C Applications For "What is object-oriented design" uncle Bob: "Object-oriented design is an engineering method, its purpose is to manage dependencies between parts in various parts Follow the object-oriented design principle, the direct dependence between service users and service providers does not exist, and the generation is dependent on the interface. In addition, more importantly, the dependencies between interfaces and service providers are completely Reverse; not the interface depends on the service provider, but the service provider relies on the interface. "
