Please describe the primary use of the double pointer in C and C++; that is, **pointer.
A pointer is simply the address of some variable. If you placed that address in another variable and then got the address of that variable, you’d have a pointer to a pointer (a double pointer). By declaring it as a pointer to a pointer, C++ is able to resolve it to the value of the original variable.
Once you get familiar with pointers, this is pretty straightforward. But if you don’t have the need for one, a double pointer is not something you need to rush out and learn how to use. Just become comfortable working with regular pointers and you will undoubtedly come across a situation where the need for a double pointer will be clear.