Sample Series of design patterns

In this series of essays, I would like to explain it as little as possible, with a concise CodeTo express the intent and applicability of the design model! Publishing a essay only represents my understanding at the time and is not necessarily correct. This series of examples is a subset of the gof design patterns. Many models are actually very similar. The difference in nuances also depends on reading more books to understand.

Design Pattern Example 1 factory Method)

Design Pattern Example 2 decorator)

Example 3 Abstract Factory (Abstract Factory)

Design Pattern Example 4 observer (observer) and iterator (iterator)