This operator returns a reference to a value some distance in memory from a base address. It is essentially shorthand for "
*(lhs + rhs)" because the reference can be thought of as a pointer having as value the memory location "
(lhs + rhs)", and which is implicitly dereferenced; both do exactly the same thing.
Like pointer arithmetic, any type of
Pointer can be indexed except for an
Any Pointer. Also, like pointer arithmetic, it is up to the user to make sure meaningful data is being accessed.
When indexing a '2-dimensional' pointer (i.e. a
T Ptr Ptr), the first (leftmost) index is applied before the second: For example,
Pt[I1][I2] =
*(Pt[I1] + I2) =
*(*(Pt + I1) + I2)
In general, when using an '
n-dimensional' pointer:
Pt[I1][I2].....[In], the index order (from left to right) corresponds to the dereferencing order.
This operator must not be used in case of null pointer because reference is undefined (inducing runtime error).
Otherwise, the user must ensure that the offset value (
rhs) is in a range that allows an access to valid memory. Outside this range, results are undefined.
This operator can be overloaded for user-defined types as a member
Operator using the appropriate syntax.