In Singleton Pattern, the class can only create a single instance. We want a class to have only a single instance for various reasons. Sometimes, we want use a global object to keep information about your program. This object should not have any copies. This information might be things like configuration of the program, or a master object that manages pools of resources. So when you need a resource, you ask the master object to get it for you. Now if there were many copies of this master object, you would not know whom to ask for that resource. This single object should not be allowed to have copies. Singleton Pattern forces this rule so that programmer doesn’t have to remember about not creating copies. Singleton pattern will create an instance if it doesn’t exist and will not create any new instance if an instance already exist. It will just return a reference to that single instance.

class ProgramConfiguration{
    public ProgramConfiguraiton(){
        //default constructor code
    }
}

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