What gof patterns are used for game development?

Question

C++ / C#

Studied GRASP patterns. As far as I understand, they are universal and simply specify the principles of OOP. Helped me develop high-quality architecture for an old project.
Next, I plan to study GoF templates, but I heard the opinion that you don’t need to know all of them. Which ones are used in game development? What does "knowledge of design patterns" mean in vacancies? How is their knowledge tested?

Answer 1

Google: two or more data types in declaration specifiers
First answer: stackoverflow.com/questions/2098973/two-or-more-da...
Forgot to put a semicolon before bool state_run Go ahead
and google if this solution doesn't work .

Answer 2

heard the opinion that you don't need to know them all

Everything may not be necessary, but the main ones (by the link the name of the popular ones) is desirable, because your team leader will mention them and you need to understand what is at stake. The rest, it is best to study in order to know how certain tasks are solved "according to the classics".
I believe that game development is no different from ordinary programming, so all popular ones are used: one , two
That you distinguish Singleton from Observer. Less often, knowledge of specific things is needed (for example, CQRS + ES), in such cases it is indicated, since 90% of developers have never even heard of them.

• What is the difference between Singleton and Observer?
  
• Write an implementation of both