) returns the address of a
block of memory of size n bytes.
A pointer variable can hold an address, e.g. as returned by
malloc. In C,
X to be a variable containing a floating point
X to be a variable containing the address of a
floating point value.
NULL can be stored in a pointer, but is not a valid
address. It is useful to indicate the end of a chain of pointers. Use
P=NULL; to store it, and
if (P == NULL) ...
to test it.