My first little Ada program

.gitignore

str_date
str_date.ali
str_date.o

Makefile

make: str_date.adb
	gnatmake str_date.adb
clean:
	rm str_date str_date.ali str_date.o

str_date.adb

with Ada.Integer_Text_IO;
with Ada.Text_IO;

procedure Str_Date is
    day  : Integer;
    month: Integer;
    year : Integer;

    function GetDayAbbr(n: Integer) return String is
    begin
        case n is
            when 1 | 21 | 31 => return "st";
            when 2 | 22 => return "nd";
            when 3 | 23 => return "rd";
            when 4 .. 20 | 24 .. 30 => return "th";
            when others => return "invalid";
        end case;
    end GetDayAbbr;

    function GetMonthName(n: Integer) return String is
    begin
        case n is
            when 1 => return "January";
            when 2 => return "February";
            when 3 => return "March";
            when 4 => return "April";
            when 5 => return "May";
            when 6 => return "June";
            when 7 => return "July";
            when 8 => return "August";
            when 9 => return "September";
            when 10 => return "October";
            when 11 => return "November";
            when 12 => return "December";
            when others => return "";
        end case;
    end GetMonthName;

begin
    Ada.Text_IO.Put("Enter year  [YYYY]: ");
    Ada.Integer_Text_IO.Get(year);
    while year < -9999 or else year > 9999 loop
        Ada.Text_IO.Put_Line("Invalid year, please try again");
        Ada.Text_IO.Put("Enter year  [YYYY]: ");
        Ada.Integer_Text_IO.Get(year);
    end loop;

    Ada.Text_IO.Put("Enter month   [MM]: ");
    Ada.Integer_Text_IO.Get(month);
    while month < 1 or else month > 12 loop
        Ada.Text_IO.Put_Line("Invalid month, please try again");
        Ada.Text_IO.Put("Enter month   [MM]: ");
        Ada.Integer_Text_IO.Get(month);
    end loop;

    Ada.Text_IO.Put("Enter day     [DD]: ");
    Ada.Integer_Text_IO.Get(day);
    while day < 1 or else day > 31 loop
        Ada.Text_IO.Put_Line("Invalid day, please try again");
    Ada.Text_IO.Put("Enter day     [DD]: ");
    Ada.Integer_Text_IO.Get(day);
    end loop;

    Ada.Text_IO.Put_Line("You entered: ");
    Ada.Text_IO.Put(GetMonthName(month));
    Ada.Text_IO.Put(day'img & GetDayAbbr(day));
    Ada.Integer_Text_IO.Put(year, width => 5);
    Ada.Text_IO.New_Line;
end Str_Date;