Help:Programming Example Prototypes: Difference between revisions

==[[Ada]]==

'''Compiler:''' [[Gnat]] (GPL 2005)

[[Category:GNAT GPL 2005]]

with Ada.Text_Io;

with Ada.Integer_text_IO;

procedure Call_Back_Example is

-- Purpose: Apply a callback to an array

-- Output: Prints the squares of an integer array to the console

-- Define the callback procedure

procedure Display(Location : Positive; Value : Integer) is

begin

Ada.Text_Io.Put("array(");

Ada.Integer_Text_Io.Put(Item => Location, Width => 1);

Ada.Text_Io.Put(") = ");

Ada.Integer_Text_Io.Put(Item => Value, Width => 1);

Ada.Text_Io.New_Line;

end Display;

-- Define an access type matching the signature of the callback procedure

type Call_Back_Access is access procedure(L : Positive; V : Integer);

-- Define an unconstrained array type

type Value_Array is array(Positive range <>) of Integer;

-- Define the procedure performing the callback

procedure Map(Values : Value_Array; Worker : Call_Back_Access) is

begin

for I in Values'range loop

Worker(I, Values(I));

end loop;

end Map;

-- Define and initialize the actual array

Sample : Value_Array := (5,4,3,2,1);

begin

Map(Sample, Display'access);

end Call_Back_Example;