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5.12 Class ARRAY

indexing

description: "Sequences of values, all of the same type or of a conforming one, accessible through integer indices in a contiguous interval"

class interface

ARRAY [G]

creation

make (minindex, maxindex: INTEGER)

-- Allocate array; set index interval to

-- minindex .. maxindex; set all values to default.

-- (Make array empty if minindex > maxindex.)

ensure

no_count: (minindex > maxindex) implies (count = 0);

count_constraint: (minindex <= maxindex) implies (count = maxindex -- minindex + 1)

make_from_array (a: ARRAY [G])

-- Initialize from the items of a.

-- (Useful in proper descendants of class ARRAY,

-- to initialize an array-like object from a manifest array.)

feature -- Initialization

make (minindex, maxindex: INTEGER)

-- Set index interval to minindex .. maxindex;

-- reallocate if necessary; set all values to default.

-- (Make array empty if minindex > maxindex.)

ensure

no_count: (minindex > maxindex) implies (count = 0);

count_constraint: (minindex <= maxindex) implies (count = maxindex -- minindex + 1)

make_from_array (a: ARRAY [G])

-- Initialize from the items of a; reallocate if

-- necessary. (Useful in proper descendants of

-- class ARRAY, to initialize an array-like object

-- from a manifest array.)

feature -- Access

entry (i: INTEGER): G

-- Entry at index i, if in index interval

-- (Redefinable synonym for item and infix "@".)

require

good_key: valid_index (i)

frozen item (i: INTEGER): G

-- Entry at index i, if in index interval

require

good_key: valid_index (i)

frozen infix "@" (i: INTEGER): G

-- Entry at index i, if in index interval

require

good_key: valid_index (i)

feature -- Measurement

count: INTEGER

-- Number of available indices

lower: INTEGER

-- Minimum index

upper: INTEGER

-- Maximum index

feature -- Comparison

is_equal (other: like Current): BOOLEAN

-- Is array made of the same items as other?

-- (Redefined from GENERAL.)

feature -- Status report

valid_index (i: INTEGER): BOOLEAN

-- Is i within the bounds of the array?

feature -- Element change

enter (v: G; i: INTEGER)

-- Replace i--th entry, if in index interval, by v.

-- (Redefinable synonym for put.)

require

good_key: valid_index (i)

ensure

inserted: item (i) = v

force (v: like item; i: INTEGER)

-- Assign item v to i--th entry.

-- Always applicable: resize the array if i falls out of

-- currently defined bounds; preserve existing items.

ensure

inserted: item (i) = v;

higher_count: count >= old count

frozen put (v: like item; i: INTEGER)

-- Replace i--th entry, if in index interval, by v.

require

good_key: valid_index (i)

ensure

inserted: item (i) = v

feature -- Resizing

resize (minindex, maxindex: INTEGER)

-- Rearrange array so that it can accommodate

-- indices down to minindex and up to maxindex.

-- Do not lose any previously entered item.

require

good_indices: minindex <= maxindex

ensure

no_low_lost: lower = minindex.min (old lower);

no_high_lost: upper = maxindex.max (old upper)

feature -- Conversion

to_c: POINTER

-- Address of actual sequence of values,

-- for passing to external (non--Eiffel) routines.

feature -- Duplication

copy (other: like Current)

-- Reinitialize by copying all the items of other.

-- (This is also used by clone.)

-- (From GENERAL.)

invariant

consistent_size: count = upper -- lower + 1;

non_negative_count: count >= 0

end

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