## Chapter 7 ##

### 99 Bottles of Beer on the Wall
    SONG_BOTTLES = 99
    print "Lyrics of the song #{SONG_BOTTLES} Bottles of Beer\n\n"

    remaining_bottles = SONG_BOTTLES
    while remaining_bottles > 0
        print "#{remaining_bottles} bottles of beer on the wall, " <<
              "#{remaining_bottles} bottles of beer.\n"            <<
              "Take one down and pass it around, "                 <<
              "#{remaining_bottles -= 1} bottles of beer on the wall.\n\n"
    end

    print "No more bottles of beer on the wall, no more bottles of beer.\n" <<
          "Go to the store and buy some more, #{SONG_BOTTLES} bottles of beer on the wall.\n"
### Deaf grandma
    MIN_YEAR = 1930
    MAX_YEAR = 1950

    print "Hello kid, what do you want from grandma? "

    request = gets.chomp
    while request.index("BYE").nil?
        if request != request.upcase
            print "HUH?!  SPEAK UP, SONNY! "
        else
            year = rand((MAX_YEAR - MIN_YEAR) + 1) + MIN_YEAR
            print "NO, NOT SINCE #{year}! "
        end
        request = gets.chomp
    end
### Deaf grandma extended
    MIN_YEAR      = 1930
    MAX_YEAR      = 1950
    BYE_MAX_TRIES = 3

    print "Hello kid, what do you want from grandma? "

    bye_tries_in_a_row = 0
    while bye_tries_in_a_row < BYE_MAX_TRIES
        request = gets.chomp
        if request.index("BYE").nil?
            bye_tries_in_a_row = 0
            if request != request.upcase
                print "HUH?!  SPEAK UP, SONNY! "
            else
                year = rand((MAX_YEAR - MIN_YEAR) + 1) + MIN_YEAR
                print "NO, NOT SINCE #{year}! "
            end
        else
            bye_tries_in_a_row += 1
            if bye_tries_in_a_row == BYE_MAX_TRIES
                break
            end
            print "I CAN'T HEAR YOU! "
        end
    end
### Leap years
    print "Hello there! We are going to get the leap years in a range, OK?\n"
    print "Starting year: "
    starting_year = gets.to_i
    print "Ending year: "
    ending_year = gets.to_i

    leap_years   = []
    current_year = starting_year

    while current_year <= ending_year
        if current_year.remainder(4) == 0  &&
            (current_year.remainder(100) != 0 || current_year.remainder(400) == 0)
            leap_years.push current_year
        end
        current_year += 1
    end

    if leap_years.length > 0
        puts "The leap years between #{starting_year} and #{ending_year} are:"
        puts leap_years
    else
        puts "There are no leap years between #{starting_year} and #{ending_year}."
    end