My_Each method, using Yield

gistfile1.rb

# Read about the yield keyword and ruby blocks.
 
# http://allaboutruby.wordpress.com/2006/01/20/ruby-blocks-101/
# http://ruby.about.com/od/beginningruby/a/Block-Parameters-And-Yielding.htm
# http://blog.codahale.com/2005/11/24/a-ruby-howto-writing-a-method-that-uses-code-blocks/
# http://www.robertsosinski.com/2008/12/21/understanding-ruby-blocks-procs-and-lambdas/
 
# Now that you know how the yield method works, try to write your
# own version of the each method without using the each method
# provided by ruby. As in, try to build my_each using only the 
# while keyword.
 
# Think about what's going on in each, if it's looping through
# the elements of an array and yielding you the individual
# element one at a time to your block. What has to happen
# to do this?
 
# Note: All ruby methods accept blocks by default.


# Creating my own "each" method, using "yield"
class Array

  def my_each
    if block_given?
      i = 0 
      while i < self.size
        yield(self[i])
        i += 1
      end
    end
  end
  
end


[2,10,12,15].my_each                    # no block
[2,10,12,15].my_each {puts 'Raymond'}   # block and no parameter
[2,10,12,15].my_each {|e| puts e * e}   # block and single parameter

# Output:

#Raymond
#Raymond
#Raymond
#Raymond
#4
#100
#144
#225