Using the observer pattern

The observer design pattern is one which is not commonly used in games, but it should be used more often by game developers as it is a very smart way to handle notifications. In the observer design pattern, a component maintains a one-to-many relationship with other components. This means when the main component changes, all the dependent components also update. Imagine a physics system. We want enemy1 and enemy2 to update as soon as the physics system updates, so we should use this pattern.

Getting ready

For this recipe, you will need a Windows machine with a working copy of Visual Studio.

How to do it…

In this recipe, we will find out how easy it is to implement the observer pattern:

1. Open Visual Studio.

2. Create a new C++ project.

3. Select a Win32 Windows application.

4. Add a source file called Source.cpp.

5. Add the following lines of code to it:

   #include <iostream>
   #include <vector>
   #include <conio.h>
   
   using namespace std;
   
   class PhysicsSystem {
     
     vector...