exercise-01.rb

=begin
Write a method called convert that takes one argument
which is a fixed temperature value in Fahrenheit.
The method returns the temperature value in Centigrade.
=end
 
=begin
http://en.wikipedia.org/wiki/Fahrenheit
TC = (TF - 32) * 5/9
TF = (TC * 9/5) + 32
=end
 
# By using a default value of -40.0 the variable is "forced" into a Float.
#   This has the side-effect (good) of returning a float as well.
def convert(temperature_in_fahrenheit = -40.0)
  temperature_in_centigrade = (temperature_in_fahrenheit - 32) * 5 / 9
end
 
puts "Default Conversion is -40ºF to " + convert.to_s + "ºC"
 
test_temperature_in_fahrenheit = -459.67
puts test_temperature_in_fahrenheit.to_s + "ºF is " + convert(test_temperature_in_fahrenheit).to_s + "ºC"
 
test_temperature_in_fahrenheit = 32
puts test_temperature_in_fahrenheit.to_s + "ºF is " + convert(test_temperature_in_fahrenheit).to_s + "ºC"
 
test_temperature_in_fahrenheit = 212
puts test_temperature_in_fahrenheit.to_s + "ºF is " + convert(test_temperature_in_fahrenheit).to_s + "ºC"

exercise-02.rb

=begin
The following program:
> arg1="Satish", arg2="Sunil", arg3="Marcos"
> puts "#{arg1}, #{arg2}, #{arg3}."
 
when executed, outputs:
> SatishSunilMarcos, Sunil, Marcos.
 
Why?
=end
 
arg1="Satish", arg2="Sunil", arg3="Marcos"
puts "#{arg1}, #{arg2}, #{arg3}."
# Because arg1 is seen by Ruby as an Array with 3 elements.
 
arg1 = [ "Satish", arg2 = "Sunil", arg3 = "Marcos" ]
puts "#{arg1}, #{arg2}, #{arg3}."
# It implictly surrounds the statement with commas with square-brackets.
 
# These following forms don't trigger arg1 to be an array:
arg1 = "Satish"; arg2 = "Sunil"; arg3 = "Marcos"
puts "#{arg1}, #{arg2}, #{arg3}."
arg1 = "Satish"
arg2 = "Sunil"
arg3 = "Marcos"
puts "#{arg1}, #{arg2}, #{arg3}."

exercise-03.rb

=begin
Write a Ruby program (p006ftoc.rb) that asks for a numeric value of the temperature in degrees Fahrenheit.
Finally, the program displays the equivalent value in degrees Centigrade.
To format the output to say 2 decimal places, we can use the Kernel's format method.
For example, if x = 45.5678 then format("%.2f", x) will return a string 45.57.
Another way is to use the round function as follows: puts (x*100).round/100.0
=end
 
=begin
http://en.wikipedia.org/wiki/Fahrenheit
TC = (TF - 32) * 5/9
TF = (TC * 9/5) + 32
=end
 
# By using a default value of -40.0 the variable is "forced" into a Float.
#   This has the side-effect (good) of returning a float as well.
def f2c(temperature_in_fahrenheit = -40.0)
  temperature_in_centigrade = (temperature_in_fahrenheit - 32) * 5 / 9
end
 
def c2f(temperature_in_centigrade = -40.0)
  temperature_in_fahrenheit = (temperature_in_centigrade - 32) * 5 / 9
end
 
puts "Conversion Options:\n\tc - Centigrade to Fahrenheit\n\tf - Fahrenheit to Centigrade "
print "Select Conversion Options: "
STDOUT.flush
conversion_option = gets.chomp
 
if conversion_option == 'c' or conversion_option == 'f' then
 
  print "Input Temperature Value to Convert "
  if conversion_option == 'c' then
    print "from Centigrades to Fahrenheit: "
  end
  if conversion_option == 'f' then
    print "from Fahrenheit to Centigrades: "
  end
  STDOUT.flush
  temperature = gets.chomp
  temperature = temperature.to_f
 
  if conversion_option == 'c' then
    puts format("%.2f", temperature.to_s) + "ºC is " + format("%.2f", c2f(temperature).to_s) + "ºF."
  end
  if conversion_option == 'f' then
    puts format("%.2f", temperature.to_s) + "ºF is " + format("%.2f", f2c(temperature).to_s) + "ºC."
  end
 
else
  puts "Unknown Conversion Option!"
end

exercise-04.rb

=begin
Write a Ruby program that prints the numbers from 1 to 100.
But for multiples of three print "Fizz" instead of the number
and for the multiples of five print "Buzz".
For numbers which are multiples of both three and five print "FizzBuzz".
 
This exercise is courtesy Chris Porter.  
=end
 
# times starts at 0
#100.times do |number|
#  number = number + 1
#  puts number.to_s
#end
 
# step starts at arg1, loops until arg2, incremented by optional arg3 = 1
1.step(100) do |number|
 
  is_multiple = false
 
  if number % 3 == 0 then
    print "Fizz"
    is_multiple = true
  end
  if number % 5 == 0 then
    print "Buzz"
    is_multiple = true
  end
 
  if !is_multiple then
    puts number.to_s
  else
    print "\n"
  end
 
end