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with Ada.Text_IO; use Ada.Text_IO;
with Ada.Strings.Unbounded; use Ada.Strings.Unbounded;
procedure Arrays is
-----------------------------------------------------------------------------
-- Arrays 101.
--
-- The index is strongly-typed and can be any discrete type.
--
-- Iterations over the index type are preferred over iterations over specific
-- index values.
-----------------------------------------------------------------------------
procedure Test_Array is
type My_Int is range 0 .. 1_000;
type Index is range 1 .. 5;
type My_Int_Array is array (Index) of My_Int;
function To_String (A : My_Int_Array) return String is
S : Unbounded_String;
begin
for I in Index loop
S := S & My_Int'Image (A (I)) & " ";
end loop;
return To_String (S);
end To_String;
Arr : My_Int_Array := (2, 3, 5, 7, 11);
-- This array is not actually empty; its size is determined by the range of
-- its index type, which in this example is 1 .. 5.
Empty_Arr : My_Int_Array;
begin
Put_Line ("Arr = " & To_String (Arr));
Put_Line ("Arr is " & Integer'Image (Arr'Size) & " bytes");
Put_Line ("Empty_Arr = " & To_String (Empty_Arr));
Put_Line ("Empty_Arr is " & Integer'Image (Empty_Arr'Size) & " bytes");
end Test_Array;
-----------------------------------------------------------------------------
-- Enums as array indices.
-----------------------------------------------------------------------------
procedure Test_Enum_Array is
type Month is (Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec);
type Day is range 1 .. 31;
Month_Days : array (Month) of Day :=
(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);
begin
for M in Month loop
Put_Line
(Month'Image (M) & " has " & Day'Image (Month_Days (M)) & " days");
end loop;
end Test_Enum_Array;
-----------------------------------------------------------------------------
-- Arrays in ADA are bounds-checked.
-----------------------------------------------------------------------------
procedure Test_Bounds is
Arr : array (Integer range 1 .. 5) of Integer := (3, 4, 7, 8, 9);
begin
Arr (1) := 17;
Arr (5) := 18;
--Arr (6) := 19; -- Error.
end Test_Bounds;
-----------------------------------------------------------------------------
-- Use the Range attribute to iterate over an array with an anonymous range.
-----------------------------------------------------------------------------
procedure Test_Anonymous_Range is
Arr : array (3 .. 7) of Integer := (5, 8, 3, 5, 3);
begin
for I in Arr'Range loop
Put_Line
("Index " & Integer'Image (I) & " has value " &
Integer'Image (Arr (I)));
end loop;
end Test_Anonymous_Range;
-----------------------------------------------------------------------------
-- Unconstrained arrays.
--
-- The size/bounds are provided when creating an instance of the array type.
-----------------------------------------------------------------------------
procedure Test_Unbounded_Array is
type Day is (Mon, Tue, Wed, Thu, Fri, Sat, Sun);
type Days_Arr is array (Integer range <>) of Day;
Days_Off : Days_Arr := (Sat, Sun);
begin
Put ("Holidays: ");
for D in Days_Off'Range loop
Put (Day'Image (Days_Off (D)) & " ");
end loop;
New_Line;
end Test_Unbounded_Array;
-----------------------------------------------------------------------------
-- Bounds are automatically inferred from the initialization value.
-----------------------------------------------------------------------------
procedure Test_Auto_Bounds is
Arr : array (Natural range <>) of Integer := (2, 3, 4);
begin
for I in Arr'First .. Arr'Last loop
Put_Line ("Arr(" & Integer'Image (I) & ") = " & Integer'Image (Arr (I)));
end loop;
end Test_Auto_Bounds;
-----------------------------------------------------------------------------
-- Array slices.
-----------------------------------------------------------------------------
procedure Test_Slices is
Str : String := "Hello world";
begin
Str (7 .. 11) := "there";
Put_Line (Str);
end Test_Slices;
begin
Test_Array;
Test_Enum_Array;
Test_Bounds;
Test_Anonymous_Range;
Test_Unbounded_Array;
Test_Auto_Bounds;
Test_Slices;
end Arrays;
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