Singleton is a simple design
pattern. It is used when you want one
global object that can be used throughout the entire project. An example when
you may want to do this is when using debug tools like a logger.
You would only like one logger in your project so that one logger is logging
your projects information out to the same file, so you do not end up with
multiple files.
In order to have one instance of
the object you need to control when the object gets initialized. One way to do
this is to do the initialization of the class in itself and to disallow the any
coping or assignment of the class. So first you make the constructor private and
disallow copy and assignment. The reason
for disallowing copy and assignment is so we do not let ourselves or anybody
else to make another instance of the object. You should end open with something like this:
Next you need to declare your instance of the class, so declare a static instance of
the class as private. Now we need a way to give access of that instance to
other classes. So make a public static function that return an address of the
class. Next define the function so it returns the static instance that you just
declared. Now
to call the single instance of the object in another class you scope into the
class and call the function that returns the class like so, “YourClass::GetTheInstance()”.
And that all this is to the Singleton design pattern.
