1  class Integer
2    def isEven?()
3      if self % 2 == 0 
4      then 
5        true
6      else 
7        false
8    end
9  end

1  class Ball
2    def initialize (color, radius, texture)
3      @color   = color
4      @radius  = radius
5      @texture = texture
6    end
7  
8    def display 
9      puts "Color   ==> "  + @color
10     puts "Radius  ==> " + @radius.to_s
11     puts "Texture ==> " + @texture
12   end
13 end

1  require 'Ball'
2  newBall = Ball.new(‘green’, 1, ‘bouncy’)
3  newBall.display

1  class Rectangle < Shape
2    def initialize (length, width, color, label)
3      super
4      @area = length * width
5    end
6
7    def display
8      super.display
9      puts("Area   ==> " + @area.to_s)
10   end
11   attr_accessor :area
12 end

1  class Savings < Account
2    def calcInterest(months, apr)
3      monthlyYield = apr/12
4      ppm = months * monthlyYield
5      accountBalance * ppm
6    end
7  end

1  class Savings < Account
2    def calcInterest(months, apr)
3      oldInt = super #assuming an amount of interest
4      monthlyYield = apr/12
5      ppm = months * monthlyYield
6      (accountBalance * ppm) + oldInt
7    end
8  end

1  class Shape
2  
3    @@numShapes = 0
4  
5    def initialize (length, width, color, label)
6      @length = length
7      @width = width
8      @color = color
9      @label = label
10     @@numShapes = @@numShapes + 1
11   end
12  
13   def display 
14     puts "Shape  ==> "  + @label
15     puts "Length ==> " + @length.to_s
16     puts "Width  ==> " + @width.to_s
17     puts "Color  ==> " + @color
18     puts "Number of Shapes ==> " + @@numShapes.to_s
19   end
20 end

1  require 'Shape'
2  require 'Rectangle' 
3
4  r1 = Rectangle.new(5,4,'blue','blue rectangle')
5  r1.display
6 
7  r2 = Rectangle.new(3,6,'red','red rectangle')
8  r2.display