How many types of pointers are there?

Answer 1

That depends on what you consider a type. A pointer variable simply stores a memory address or NULL so, strictly speaking, there is only one type of pointer.

A pointer variable's type (int *, char *, void *, etc) determines the type that a pointer points to, not the type of the pointer itself. Whether a pointer points to a primitive type, a user-defined type, a function, another pointer or void, makes no difference to the pointer variable itself. It simply stores a memory address. How you treat that memory address is determined by the pointer variable's type. So, in that respect, there are as many types of pointer as there are types to point at; which would be infinite.

The architecture determines the size of a pointer variable. On a 16-bit system, a pointer will occupy just 2 bytes, while on a 32-bit system it occupies 4 bytes and 8 bytes on a 64-bit system. Although these may be considered separate pointer types, you can't pick and choose which type you use. The size must be consistent for any given architecture, hence the prevalent use of the sizeof() operator to determine a variable's length at runtime.