Description |
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One of the operands of the subscript operator must be of type
pointer to T
(T is an object
type), the other of integral type. The resulting type is T.
The [ ]
operator is defined so that E1[E2]
is identical to (*((E1)+(E2)))
in every respect. This leads to the (counterintuitive) conclusion
that the [ ]
operator is commutative. The expression E1[E2]
is identical to E2[E1].
C's subscripts run from 0
to n-1 where
n is the array
size.
Multidimensional arrays are represented as arrays of arrays.
For this reason, the notation is to add subscript operators, not
to put multiple expressions within a single set of brackets. For
example, int x[3][5]
is actually a declaration for an array of three objects. Each object
is, in turn, an array of five int. Because of this, all of the following
expressions are correct:
The first expression refers to the 3 by 5 array of int. The
second refers to an array of five int, and the last expression refers
to a single int.
The expression x[y]
is an lvalue.
There is no arbitrary limit on the number of dimensions that
you can declare in an array.
Because of the design of multidimensional C arrays, the individual
data objects must be stored in row-major order.
As another example, the expression
looks as if array a
were doubly subscripted, when actually the comma in the subscript
indicates that the value of i
should be discarded and that j
is the subscript into the a
array.
