What does int * arr [] mean?

If used like like this, that is inside a function declaration/definition it in fact defines an int **, a pointer to pointer to int. In the context of a function declaration/definition int * arr and int ** arr are equivalent, or more general T* equals T**. To explicitly state this: In no case int * arr defines any int s. size of what?

What does A/R stand for?

Definition. A/R. As Required. A/R. Accounts Receivable. A/R. Andata e Ritorno (Italian: Forward and Backward/Out and Home/First and Last Half) A/R. Area/Radius (geometry)

What does XR stand for?

XR encompasses augmented reality (AR), virtual reality (VR), and mixed reality (MR). While all three ‘realities’ share common overlapping features and requirements, each has different purposes and underlying technologies. XR is set to play a fundamental role in the metaverse.