14.5 Dereferencing Pointers

The main use of a pointer value is to dereference it (access the data it points at) with the unary ‘*’ operator. For instance, *&i is the value at i’s address—which is just i. The two expressions are equivalent, provided &i is valid.

A pointer-dereference expression whose type is data (not a function) is an lvalue.

Pointers become really useful when we store them somewhere and use them later. Here’s a simple example to illustrate the practice:

{
  int i;
  int *ptr;

  ptr = &i;

  i = 5;

  …
  
  return *ptr;   /* Returns 5, fetched from i.  */
}

This shows how to declare the variable ptr as type int * (pointer to int), store a pointer value into it (pointing at i), and use it later to get the value of the object it points at (the value in i).

If anyone can provide a useful example which is this basic, I would be grateful.