What is the significance of the dependency inversion principle in software design?

The Dependency Inversion Principle (DIP) states that high-level modules should not depend on low-level modules directly. Instead, both should depend on abstractions (such as interfaces or abstract classes). Abstractions should not depend on details, but details should depend on abstractions.

This reduces coupling between components, makes testing easier, and increases system flexibility. For example, instead of a class directly creating an instance of another class, it receives it through an interface, which allows easy changing of the implementation without modifying the client code.