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For 2021 - online Python 3 training - see ((here)).

Our plans were to retire in summer 2020 and see the world, but Coronavirus has lead us into a lot of lockdown programming in Python 3 and PHP 7.
We can now offer tailored online training - small groups, real tutors - works really well for groups of 4 to 14 delegates. Anywhere in the world; course language English.

Please ask about private 'maintenance' training for Python 2, Tcl, Perl, PHP, Lua, etc.
An example of Java Inheritance from scratch

One of the most important topics for newcomers to OO (Object oriented) programming to learn is how to design their classes and make best use of inheritance, and I find myself writing new examples from first principles during our courses. That way, the delegates learn how to actually do the job - they're NOT just presented with a "here is one I wrote earlier" and left to struggle!

In order to let the delegates then refer to the code I wrote, I've put it up on our wiki ... the web formatting isn't very tidy, but it's a great "all in one place" reference for them when they come to do their own practical.

The first example is at http://www.wellho.net/share/javainherit.html. It's a base class called "Animal" with two subclasses called "Farm" and "Pet" with the whole thing being tested by "Anitest". The beauty of using inheritance in this way is that you can put the common code in "Animal" and then just the farm-specific or pet-specific stuff into the Farm and Pet classes - saves code duplication.

That first example isn't perfect, though. We want to extend it as follows:
a) To have an array of animals that we can loop through
b) To use a utility function to handle multiple similar methods
c) To provide static methods than work on the whole
d) To set up Animal such that we can force all extended classes to have specific enhancements ("abstract")
e) To provide functions to compare two or more objects in a way we define.
These extras are in my second example at http://www.wellho.net/share/javainherit2.html.
(written 2007-08-08, updated 2014-11-05)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
J706 - Java - Objects and Classes
  [96] Variable Scope - (2004-10-22)
  [477] Class, static and unbound variables - (2005-10-25)
  [1163] A better alternative to cutting and pasting code - (2007-04-26)
  [1500] First Class Java. First step and moving forward. - (2008-01-10)
  [1906] Long, Longer, Longest in Java - (2008-11-25)
  [1925] Introduction to Object Oriented Programming - (2008-12-06)
  [2169] When should I use OO techniques? - (2009-05-11)
  [2422] Looking inside Java classes - javap and javadoc - (2009-09-25)
  [2616] Defining a static method - Java, Python and Ruby - (2010-02-01)
  [2651] Calculation within objects - early, last minute, or cached? - (2010-02-26)
  [4413] Binomial Coefficient (Pascal Triangle) objects in Java - (2015-02-03)
  [4422] Objects - from physical to virtual or abstract - Java - (2015-02-10)


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This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

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