The month of October in 2010 has five Fridays, five Saturdays, and five Sundays.



Task

 Write a program to show all months that have this same characteristic of five full weekends from the year 1900 through 2100 (Gregorian calendar). 
 Show the number of months with this property (there should be 201).
 Show at least the first and last five dates, in order.

Algorithm suggestions

 Count the number of Fridays, Saturdays, and Sundays in every month.
 Find all of the 31-day months that begin on Friday.

Extra credit

Count and/or show all of the years which do not have at least one five-weekend month (there should be 29).



Related tasks
 Day of the week
 Last Friday of each month
 Find last sunday of each month


 
with Ada.Text_IO;              use Ada.Text_IO;
with Ada.Calendar.Formatting;  use Ada.Calendar;
 
use Ada.Calendar.Formatting;
 
procedure Five_Weekends is
   Months : Natural := 0;
begin
   for Year in Year_Number range 1901..2100 loop
      for Month in Month_Number range 1..12 loop
         begin
            if Day_Of_Week (Formatting.Time_Of (Year, Month, 31)) = Sunday then
               Put_Line (Year_Number'Image (Year) & Month_Number'Image (Month));
               Months := Months + 1;
            end if;
         exception
            when Time_Error =>
               null;
         end;
      end loop;
   end loop;
   Put_Line ("Number of months:" & Integer'Image (Months));
end Five_Weekends;
 