Class_Attribute_counting_example.rb

# Class counting example.rb

# An example of using a hash to count attributes stored in a class.

class Course
  attr_accessor :name, :dept, :credits

	def initialize (name, dept, credits)
		@name = name
		@dept = dept
		@credits = credits
	end
end

def count_dept_credits_taken(array_of_course_objects)
	dept_credits = Hash.new(0)
	array_of_course_objects.each do |course|
		dept_credits[course.dept] += course.credits
	end

	dept_credits
end

# English courses
basic_english = Course.new("English 101", "English", 5)
great_novels = Course.new("English 132", "English", 3)
biz_writing = Course.new("English 201", "English", 2)

# A non-English Course

computers = Course.new("CSE 142", "Comp-Sci", 5)

course_list = [basic_english, great_novels, biz_writing, computers]

p count_dept_credits_taken(course_list)

# Returns {"English" => 10, "Comp-Sci" = 5}