C++ Programming - OOPS Concepts - Discussion

What is meant by singleton class?

How we create singleton class?

So the class derived as private is called singleton class?

When class having only one class is called singleton class;

Means that single=means one it means that required of one object.

A Singleton class is a design pattern, which creates only a single instance at any time.

When is it required:

Based on the requirement.

Example : Singletons are often used to control access to resources such as database connections or sockets.

Suppose u have licence for only one connection for database, A singleton connection obj makes sure that only one connection can be made at any time.

How this can be implemented:

1. Have a static method, creates the instance if the instance does not exists. If the instance already there then returns the reference to the existing obj.

2. Have a private constructor.

Why Static method:

No obj is required to call static method and memory is used only when required.

private constructor is to make sure that object is not created in any other way.

I explained as per my knowledge. Hope this would be useful.

I can't understand following statement:

static A* m_objA;

And Also term Singleton & Longer class.

Singleton class has only one instance this concept given in the design pattern.

What is the use of singleton class? please give me simple explanation.

A class which is having only single object is called singleton.

Can I get more info about singltone class.