Task: Cheryl's birthday








VB: Private Sub exclude_unique_days(w As Collection)
    Dim number_of_dates(31) As Integer
    Dim months_to_exclude As New Collection
    For Each v In w
        number_of_dates(v(1)) = number_of_dates(v(1)) + 1
    Next v
    For i = w.Count To 1 Step -1
        If number_of_dates(w(i)(1)) = 1 Then
            months_to_exclude.Add w(i)(0)
            w.Remove i
        End If
    Next i
    For Each m In months_to_exclude
        exclude_month w, m
    Next m
End Sub
Private Sub exclude_month(x As Collection, v As Variant)
    For i = x.Count To 1 Step -1
        If x(i)(0) = v Then x.Remove i
    Next i
End Sub
Private Sub exclude_non_unique_days(w As Collection)
    Dim number_of_dates(31) As Integer
    For Each v In w
        number_of_dates(v(1)) = number_of_dates(v(1)) + 1
    Next v
    For i = w.Count To 1 Step -1
        If number_of_dates(w(i)(1)) > 1 Then
            w.Remove i
        End If
    Next i
End Sub
Private Sub exclude_non_unique_months(w As Collection)
    Dim months As New Collection
    For Each v In w
        On Error GoTo 1
        months.Add v(0), v(0)
    Next v
1:
    For i = w.Count To 1 Step -1
        If w(i)(0) = v(0) Then
            w.Remove i
        End If
    Next i
End Sub
Public Sub cherylsbirthday()
    Dim v As New Collection
    s = "May 15, May 16, May 19, June 17, June 18, July 14, July 16, August 14, August 15, August 17"
    t = Split(s, ",")
    For Each u In t
        v.Add Split(Trim(u), " ")
    Next u
    
    exclude_unique_days v
    
    exclude_non_unique_days v
    
    exclude_non_unique_months v
    Debug.Print v(1)(0); " "; v(1)(1)
End Sub




Ada: with Ada.Text_IO; use Ada.Text_IO;

procedure Main is
   type Months is
     (January, February, March, April, May, June, July, August, September,
      November, December);
   type day_num is range 1 .. 31;
   type birthdate is record
      Month  : Months;
      Day    : day_num;
      Active : Boolean;
   end record;

   type birthday_list is array (Positive range <>) of birthdate;

   Possible_birthdates : birthday_list :=
     ((May, 15, True), (May, 16, True), (May, 19, True), (June, 17, True),
      (June, 18, True), (July, 14, True), (July, 16, True), (August, 14, True),
      (August, 15, True), (August, 17, True));

   procedure print_answer is
   begin
      for the_day of Possible_birthdates loop
         if the_day.Active then
            Put_Line (the_day.Month'Image & "," & the_day.Day'Image);
         end if;
      end loop;
   end print_answer;

   procedure print_remaining is
      count : Natural := 0;
   begin
      for date of Possible_birthdates loop
         if date.Active then
            count := count + 1;
         end if;
      end loop;
      Put_Line (count'Image & " remaining.");
   end print_remaining;

   
   procedure first_pass is
      count : Natural;
   begin
      for first_day of Possible_birthdates loop
         count := 0;
         for next_day of Possible_birthdates loop
            if first_day.Day = next_day.Day then
               count := count + 1;
            end if;
         end loop;

         if count = 1 then
            for the_day of Possible_birthdates loop
               if the_day.Active and then first_day.Month = the_day.Month then
                  the_day.Active := False;
               end if;
            end loop;
         end if;
      end loop;
   end first_pass;

   
   procedure second_pass is
      count : Natural;
   begin
      for first_day of Possible_birthdates loop
         if first_day.Active then
            count := 0;
            for next_day of Possible_birthdates loop
               if next_day.Active then
                  if next_day.Day = first_day.Day then
                     count := count + 1;
                  end if;
               end if;
            end loop;

            if count > 1 then
               for next_day of Possible_birthdates loop
                  if next_day.Active and then next_day.Day = first_day.Day then
                     next_day.Active := False;
                  end if;
               end loop;
            end if;
         end if;
      end loop;
   end second_pass;

   
   procedure third_pass is
      count : Natural;
   begin
      for first_day of Possible_birthdates loop
         if first_day.Active then
            count := 0;
            for next_day of Possible_birthdates loop
               if next_day.Active and then next_day.Month = first_day.Month
               then
                  count := count + 1;
               end if;
            end loop;
            if count > 1 then
               for next_day of Possible_birthdates loop
                  if next_day.Active and then next_day.Month = first_day.Month
                  then
                     next_day.Active := False;
                  end if;
               end loop;
            end if;
         end if;
      end loop;
   end third_pass;

begin
   print_remaining;
   first_pass;

   print_remaining;
   second_pass;

   print_remaining;
   third_pass;

   print_answer;
end Main;