Collection of Tools & Utilities/Collection of Tools and Utilities.iso/ada/gwuada_8.zip/DOC.ZIP/FIBB.ADA

Text File | 1993-08-17 | 2KB | 60 lines

--
--    Program : Fibb.ada
--    Purpose : This program calculates a fibbinochi number.  This number
--        is calculated by summing all the numbers up to and including
--        that number.  For example, 4 would be
--
--            1 + 2 + 3 + 4 = 10
--
--        It is similar to a factorial, but the growth of the number
--        is much slower, and so we can use it with a much larger
--        level of recursion.
--
--    To use with GWUMON : To use this program with GWUMON, from the command
--              line type:
--                       adacomp -a -b -mfibbinochi fibb.ada
--                       gwumon -mfibbinochi
--
--    Take the default options on the first screen (speed = 6, exceptions = yes,
--              and tasks = no) by hitting the "Esc" key.  Change from a Small
--        Window to a Large Window on the second screen.
--
--    The purpose of this program is to show a large amount of recursion.
--    Therefore, when prompted for the number to be calculated, choose 13.
--    This will cause the program to recursively call Fibb_Calc 13 times.
--
--    Notice that each time Fibb_Calc is called, a new window is opened until
--    a total of 12 windows are opened.  At that point, no new windows are
--    created, but notice that the highest level window "Scrolls" off to the
--    upper right and is no longer visable.
--
--    When the program has gotten to the final window, notice how it begins
--    to scrool the windows back on to the screen as the call stack unwinds.
--    When all the programs on the stack are back on the screen, the stack
--    continues to unwind, until there is only a single procedure left on
--    the screen.  This shows the call stack, and the recursion of the program.
--
WITH Text_IO;
PACKAGE My_Int_IO IS
  NEW Text_IO.Integer_IO (Num => Integer);

WITH Text_IO; USE Text_IO;
WITH My_Int_IO; USE My_Int_IO;
PROCEDURE Fibbinochi IS
    Temp : Integer;
    FUNCTION Fibb_Calc( Current_Num: IN Integer ) RETURN Integer is
    BEGIN
        IF Current_Num = 0
        THEN
            RETURN 0;
        END IF;
        RETURN Current_Num + Fibb_Calc( Current_Num - 1 );
    END Fibb_Calc;
BEGIN
    PUT_LINE( "Enter the Fibbinochi number to be calculated" );
    GET( Temp );
    Temp := Fibb_Calc( Temp );
    My_Int_IO.PUT( Item => Temp );
END Fibbinochi;