Data commit

Task/Polymorphism/Ruby/polymorphism-1.rb

@@ -0,0 +1,23 @@
+class Point
+  attr_accessor :x,:y
+  def initialize(x=0, y=0)
+    self.x = x
+    self.y = y
+  end
+  def to_s
+    "Point at #{x},#{y}"
+  end
+end
+
+# When defining Circle class as the sub-class of the Point class:
+class Circle < Point
+  attr_accessor :r
+  def initialize(x=0, y=0, r=0)
+    self.x = x
+    self.y = y
+    self.r = r
+  end
+  def to_s
+    "Circle at #{x},#{y} with radius #{r}"
+  end
+end

Task/Polymorphism/Ruby/polymorphism-2.rb

@@ -0,0 +1,15 @@
+# create a point
+puts Point.new          # => Point at 0,0
+p = Point.new(1, 2)
+puts p                  # => Point at 1,2
+puts p.x                # => 1
+p.y += 1
+puts p                  # => Point at 1,3
+
+# create a circle
+c = Circle.new(4,5,6)
+# copy it
+d = c.dup
+d.r = 7.5
+puts c                  # => Circle at 4,5 with radius 6
+puts d                  # => Circle at 4,5 with radius 7.5