C++ Programming - OOPS Concepts - Discussion

@Kalaivani.

Singleton class is one whose only one instance (object) can be created. The object is declared globally so that we can use it anywhere in the program.

But this should be avoided as per the fundamental principles like encapsulation or data hiding. Singleton class can also be created by using all static methods which require no instance to call a method.

Eg:-

In the case of an atm machine when we insert our card, an instance is created for our account and all the transactions are created using that single instance of that card.

Give more explanation for singleton class with clear example.

Singleton used in the development of an application like public chat, cricket score.

Can we use any other class, other than singleton class?

I too didn't understand this singleton class.

What is friend class? Explain?

Please explain in this question in details.

Only single class can be inherited, no multiple inheritance can take place here.

Singleton set is used for only one instance of the class.

Singleton means only one instance or object at a time can be created.

Singleton set example:

public class singleton();
{
private static singleton instance;
private singleton()
{

}

Public static singleton instance (this is one and only one way to obtain any instance of the singleton set).
{
get
{
if(instance==null)
{
instanece = new singleton(); (memory will be allocated only on first call to the 'instance' property)
}
return instance;
}
}

If it is singleton, explain others?