Design patterns

I have wondered for a while, why people keep talking about design patterns, and looks like i should have studied this long time back - reason - because if nothing else they are an effective benchmark to differentiate one language from another.

Have a look at this article by Paul Graham about how 2 different 1950 paradigms

1. Lisp
2. Fortran

Have been converging over the years.

Also, of course, i do not know all the patterns listed here, but learning them http://en.wikipedia.org/wiki/Software_design_pattern#Classification_and_list. I suspect i have used some of these patterns without knowing their names, though good to know them formally.

Broadly speaking there are 3 types of design patterns [ ref: this ]

1. Structural: patterns generally deal with relationships between entities, making it easier for these entities to work together. e.g. a Decorator which will add some tags to the URL based on context. 
2. Creational: patterns provide instantiation mechanisms, making it easier to create objects in a way that suits the situation.e.g. Factory, similar to an adaptor/wrapper for "creating" different types of objects. Another example is the Singleton design pattern: here is a quick link for the difference between a singleton pattern and a static class (note that a static class is a concept that is in C#, not in C++). Singleton's lead to objects that can be passed as arguments etc
3. Behavioral : patterns are used in communications between entities and make it easier and more flexible for these entities to communicate e.g. Strategy pattern, adapter/wrapper