Chapter 05.markdown

Chapter 2

Hours in a year (assuming is not a leap year)

hours_per_year = 365*24
puts hours_per_year

Minutes in a decade

minutes_per_decade = hours_per_year*10*60
puts minutes_per_decade

Your age in seconds

today = Time.now
bday = Time.utc(1976,3,2,15,0,0)
puts today-bday

Our dear author's age

authors_seconds_lived = 1025000000
authors_age = (((authors_seconds_lived/60)/60)/24)/365

puts authors_age

Chapter 5

Full name greeting

puts 'Hello! What\'s your first name?'
first_name = gets.chomp
puts 'Do you have a middle name?'
middle_name = gets.chomp
puts 'What\'s your family name?'
last_name = gets.chomp
puts 'Hello ' + first_name + ' ' + middle_name + ' ' + last_name
puts 'Nice to meet you ' + ':-)'

Bigger, better favorite number

puts 'Hello estranger! what\'s your favorite number?'
favorite_number = gets
better_favorite_number = favorite_number.to_i + 1
puts 'You should better have ' + better_favorite_number.to_s

Chapter 06.markdown

Chapter 6

Angry boss

puts 'What do you want now?'
question = gets.chomp
answer = 'WHADDAYA MEAN "' + question.upcase + '"?!? YOU\'RE FIRED!!'
puts answer

Table of contents

puts 'Table of contents'.center(48)
puts ''
puts 'Chapter 1: Getting Started               page  1'
puts 'Chapter 2: Getting Started               page  9'
puts 'Chapter 3: Getting Started               page 13'

Chapter 07.markdown

Chapter 7

99 Bottles of Beer on the Wall

objects_name = "bottle"
total_objects_on_the_wall = 99
object_type = ""

while true
  puts "What do you want to count?"
  object_type = gets.chomp
  if object_type != "" 
      break
  end
end

while total_objects_on_the_wall>0
  if total_objects_on_the_wall>1 
          plural = "s"
  else 
          plural = "" 
  end
  print "#{total_objects_on_the_wall} #{objects_name+plural} of #{object_type} on the wall, "
  puts  "#{total_objects_on_the_wall} #{objects_name+plural} of #{object_type}."
  total_objects_on_the_wall = total_objects_on_the_wall-1 
end

plural = "s"
total_objects_on_the_wall

puts "No more #{objects_name+plural} of #{object_type} on the wall, no more #{objects_name} of #{object_type}."
puts "Go to the store and buy some more, #{total_objects_on_the_wall} #{objects_name+plural} of #{object_type} on the wall."

Deaf grandma

puts "HELLO SONNY, HOW ARE YOU?"

while true
        sonny_question = gets.chomp
        if sonny_question == sonny_question.upcase
                puts "NO, NOT SINCE 1938!"
                break
        end
        puts "HUH?! SPEAK UP, SONNY!"
end    

Deaf grandma extended

puts "HELLO SONNY, HOW ARE YOU?"

while true
        sonny_question = gets.chomp
        if sonny_question == "BYE"
                puts "AND THEN..."
                break   
        end
        if sonny_question == sonny_question.upcase
                random_year = 1928 + rand(80)
                puts "NO, NOT SINCE #{random_year}!"
                puts "WHAT ELSE SONNY?"
        else    
           puts "HUH?! SPEAK UP, SONNY!"
        end
end  

Leap years

puts "This program will show all the leap years in a given range"

while true
        puts "Starting year: "
        start_year = gets.to_i
        puts "Ending year: "
        end_year  =  gets.to_i
        if start_year.to_i >=0 and end_year>start_year 
               break
        else
            puts "This is an invalid range."
        end
end

current_year = start_year


while current_year < end_year
        if (current_year%4 == 0 and current_year%100!=0) || current_year%400!=0
                puts "Leap year #{current_year}"   
        end
        current_year = current_year+1
end

Chapter 08.markdown

Chapter 8

Building and sorting an array

def clear
    if RUBY_PLATFORM =~ /linux|i686-darwin9/ then
            system "clear"
    elsif RUBY_PLATFORM =~ /mswin32/ then
            system "cls"
    end
end


def msg(str,col_width)
    puts "=".center(col_width,"=")
    puts str.center(col_width)
    puts "=".center(col_width,"=")
end


clear
instructions=[]
instructions.push "Please enter as many words as you want"
instructions.push "[only one word per line]"
instructions.push "to exit, enter an empty line"
longest_line = 0
instructions.each do |inst|
    if longest_line<inst.length
            longest_line = inst.length 
    end
end

longest_line += 10

puts "=".center(longest_line,"=")
instructions.each do |inst|
    puts inst.center(longest_line)
end
puts "=".center(longest_line,"=")

text_list =[]

while true
    item_on_list = gets
    if item_on_list.include? " " 
            msg("Remember, one word per line",longest_line)
    elsif item_on_list.length == 1 
             msg("Good Bye!",longest_line)
            break
    else
            text_list.push item_on_list
    end
end

if text_list.length>0
    clear
    msg("YOUR SORTED WORD LIST",longest_line)
    puts ""
    sorted_words = text_list.sort
    sorted_words.each do |word|
            puts "#{sorted_words.index(word)+1}.- #{word}"
    end
    puts ""
    puts "=".center(longest_line,"=")
end

Table of contents, revisited

def clear
        if RUBY_PLATFORM =~ /linux|i686-darwin9/ then
           system "clear"
           line_width = terminal_size()[0]
        elsif RUBY_PLATFORM =~ /mswin32/ then
           system "cls"
           line_width = 90
        end
        line_width
end

def terminal_size
            `stty size`.split.map { |x| x.to_i }.reverse
end

line_width = clear

contents =[["Getting Started",1],["Numbers",9],["Letters",13]]
puts "_".center(line_width,"_")
puts "Table of Contents".center(line_width)
puts "_".center(line_width,"_")
puts ""
contents.each do |chapters|
    if chapters[1]>9
            fix_page_space = ""
    else
            fix_page_space =" "
    end
    title_col = "    Chapter #{contents.index(chapters)+1}: #{chapters[0]}"
    print title_col
    puts  "page #{fix_page_space}#{chapters[1]}".rjust(line_width-title_col.length-4,".")
end     
puts ""
puts "_".center(line_width,"_")

Chapter 09.markdown

Chapter 9

Improved ask method

#!/usr/bin/ruby

def set_defaults
  if RUBY_PLATFORM =~ /linux|i686-darwin9/ then
     system "clear"
     terminal_size = `stty size`.split.map { |x| x.to_i }.reverse
     line_width = terminal_size[0]
  elsif RUBY_PLATFORM =~ /mswin32/ then
     system "cls"
     line_width = 90
  else
     line_width = 90
  end
     line_width
end

def randomize_array(arr)
   arr.sort_by{rand}
end

def get_random_item(arr)
   seed = rand(arr.length-1)
   arr[seed]
end

def hr(width,char='_')
      puts char.center(width,char)
end

def ask question
    while true
      puts question
        case gets.chomp.downcase
            when 'yes' then
                    if question.rindex(/bed/) == nil
                       $order.push question.sub(/\?/,'').scan(/\b\w*$/).join
                    end
                    return true
            when 'no'  then return false
            else puts 'Please answer "yes" or "no"'
        end
    end
end

food     = ["tacos","burritos","chimichangas","sopapillas","flautas"]
drinks   = ["horchata","margaritas","tequila"]
personal = ["wet the bed"]
line_width = set_defaults
hr(line_width)
puts 'Hello stranger. Welcome to "El Taco Grande"'.center(line_width)
puts 'We have some sugestions on our menu'.center(line_width)
hr(line_width)
puts

random_food = randomize_array(food)

$order = []

food.each do |item|
   ask "Do you like #{item}?"
   if item == random_food[0]
           ask "Do you #{get_random_item(personal)}"
   elsif item == random_food[1]
           ask "Do you like drinking #{get_random_item(drinks)}"
   end
end

set_defaults
puts
puts "DEBRIEFING:"
hr(line_width,"=")
puts 'THANK YOU!'.center(line_width)
hr(line_width)
puts "Order details".center(line_width)
$order.each do |item|
   puts item.center(line_width)
end
hr(line_width)
puts
puts "your order will be ready in 45 minutes!".center(line_width)
puts
hr(line_width)

Old-school Roman numerals

def set_defaults if RUBY_PLATFORM =~ /linux|i686-darwin9/ then system "clear" terminal_size = stty size.split.map { |x| x.to_i }.reverse line_width = terminal_size[0] elsif RUBY_PLATFORM =~ /mswin32/ then system "cls" line_width = 90 else line_width = 90 end line_width end

def arabic_to_roman number
    
    if number <=0 || number>3000    
            return "The entered value can not be represented as a Roman Number"
    end
    
    roman_numeral = ""
    numbers_equiv = [[1000,"M"],[500,"D"],[100,"C"],[50,"L"],[10,"X"],[5,"V"],[1,"I"]]
    roman_set = [0,0,0,0,0,0,0]
    
    numbers_equiv.each_index do |set|
       if number >= numbers_equiv[set][0]
          roman_set[set] = number/numbers_equiv[set][0]
          number -= roman_set[set]*numbers_equiv[set][0]
       end
    end
    
    roman_set.each_index do |current|
       roman_set[current].times { roman_numeral += numbers_equiv[current][1] }
    end
    "Your Roman Number is: #{roman_numeral}"
end 
    
line_width = set_defaults

while true
    puts "_".center(line_width,"_")
    puts "Enter a number to convert".center(line_width)
    puts "to exit type [x]".center(line_width)
    puts "_".center(line_width,"_")
    puts
    print "Number: "
    num = gets.chomp
    if num == 'x'
       set_defaults
       puts "Bye!"
       break
    end
    set_defaults
    puts "_".center(line_width,"_")
    puts "  #{arabic_to_roman num.to_i}  ".center(line_width,"#")
    puts "_".center(line_width,"_")
    puts
end

Modern Roman numerals

$line_width = 90

def set_defaults
   if RUBY_PLATFORM =~ /linux|i686-darwin9/ then
      system "clear"
      terminal_size = `stty size`.split.map { |x| x.to_i }.reverse
      $line_width = terminal_size[0]
   elsif RUBY_PLATFORM =~ /mswin32/ then
       system "cls"
   end
end

def arabic_to_roman number
    if number <=0 || number>3000
       return "The entered value can not be represented as a Roman Number"
    end
    roman_numeral = ""
    # I Like Arrays
    numbers_equiv = [
       [1000,"M"],
       [900,"CM"],
       [500,"D"],
       [400,"CD"],
       [100,"C"],
       [90,"XC"],
       [50,"L"],
       [40,"XL"],
       [10,"X"],
       [9,"IX"],
       [5,"V"],
       [4,"IV"],
       [1,"I"]
    ]
    # Maybe in this one, I should used the {X=>"Y"} syntaxist, but ... nhe... latter
    numbers_equiv.each do |set|
       if number >= set[0]
          to_roman = number.divmod(set[0])
          roman_numeral += set[1]*to_roman[0]
          number = to_roman[1]
       end
    end
    "Your Roman Number is: #{roman_numeral}"
end

set_defaults

while true
    puts "_".center($line_width,"_")
    puts "Enter a number to convert".center($line_width)
    puts "to exit type [x]".center($line_width)
    puts "_".center($line_width,"_")
    puts
    print "Number: "
    num = gets.chomp
    if num == 'x'
       set_defaults
       puts "Bye!"
       break
    end
    set_defaults
    puts "_".center($line_width,"_")
    puts "  #{arabic_to_roman num.to_i}  ".center($line_width,"#")
    puts "_".center($line_width,"_")
    puts
end

Chapter 10.markdown

Chapter 10

##Sorting

#!/usr/bin/ruby

#This was Paul Idea... I am afraid of doing this kind of stuff, and check... ruby arry[].sort is not using it... class String include Comparable alias_method :old_compare, :"<=>" def <=>(other) self.downcase.old_compare(other.downcase) end

end

def array_sort arr recursive_sort arr, [] end

def recursive_sort unsorted, sorted return sorted if unsorted.length < 1

to_sort = []        
word = unsorted.shift

unsorted.each do |element|
    if  element < word
        to_sort.push word
        word = element
    else
        to_sort.push element
    end 
end 

sorted.push word

recursive_sort to_sort, sorted

end

test =[ "Sinaloa","Chihuahua","Nuevo León","Tamaulipas", "Sonora","Nayarit","baja California", "Baja California Sur", "Coahuila","Zacatecas","Durango","Guanajuato","Jalisco", "Veracruz","San Luis Potosí", "a","aa", "aaab", "ab" ]

puts "===== my sort =====" puts array_sort test puts puts "==== sort method ====" puts test.sort

Shuffle

Dictionary sort

Expanded english_number

Wedding number

Ninety-nine Bottles of Beer on the Wall

Chapter 11.markdown

Chapter 11

Safer picture downloading

Build your own playlist

Build a better playlist

Chapter 12.markdown

Chapter 12

One billion seconds!

Happy birthday!

Party like it's roman_to_integer 'mcmxcix'!

Birthday helper!

Chapter 13.markdown

Chapter 13

Extend the built-in classes

Orange tree

Interactive baby dragon

Chapter 14.markdown

Chapter 14

Even better profiling

Grandfather clock

Program logger

Better program logger