[matlab/en] Added simple class example to Matlab

matlab.html.markdown

@@ -3,6 +3,7 @@ language: Matlab
 contributors:
     - ["mendozao", "http://github.com/mendozao"]
     - ["jamesscottbrown", "http://jamesscottbrown.com"]
+    - ["Colton Kohnke", "http://github.com/voltnor"]
 
 ---
 
@@ -464,6 +465,59 @@ mean    % mean value
 std     % standard deviation
 perms(x) % list all permutations of elements of x
 
+
+% Classes
+% Matlab can support object-oriented programming. 
+% Classes must be put in a file of the class name with a .m extension. 
+% To begin, we create a simple class to store GPS waypoints.
+% Begin WaypointClass.m
+classdef WaypointClass % The class name.
+  properties % The properties of the class behave like Structures
+    latitude 
+    longitude 
+  end
+  methods 
+    % This method that has the same name of the class is the constructor. 
+    function obj = WaypointClass(lat, lon)
+      obj.latitude = lat;
+      obj.longitude = lon;
+    end
+
+    % Other functions that use the Waypoint object
+    function r = multiplyLatBy(obj, n)
+      r = n*[obj.latitude];
+    end
+
+    % If we want to add two Waypoint objects together without calling
+    % a special function we can overload Matlab's arithmetic like so:
+    function r = plus(o1,o2)
+      r = WaypointClass([o1.latitude] +[o2.latitude], ...
+                        [o1.longitude]+[o2.longitude]);
+    end
+  end
+end
+% End WaypointClass.m
+
+% We can create an object of the class using the constructor
+a = WaypointClass(45.0, 45.0)
+
+% Class properties behave exactly like Matlab Structures.
+a.latitude = 70.0
+a.longitude = 25.0
+
+% Methods can be called in the same way as functions
+ans = multiplyLatBy(a,3)
+
+% The method can also be called using dot notation. In this case, the object 
+% does not need to be passed to the method.
+ans = a.multiplyLatBy(a,1/3)
+
+% Matlab functions can be overloaded to handle objects. 
+% In the method above, we have overloaded how Matlab handles 
+% the addition of two Waypoint objects.
+b = WaypointClass(15.0, 32.0)
+c = a + b
+
 ```
 
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