http://wiki.karljones.com/index.php?action=history&feed=atom&title=Circle-ellipse_problem 2026-10-23T15:07:20Z Revision history for this page on the wiki MediaWiki 1.24.2 http://wiki.karljones.com/index.php?title=Circle-ellipse_problem&diff=17755&oldid=prev 2016-09-04T15:21:13Z

<p>Created page with &quot;In <a href="/index.php/Software_development" title="Software development">software development</a>, the &#039;&#039;&#039;circle-ellipse problem&#039;&#039;&#039; (sometimes termed the square-rectangle problem) illustrates several pitfalls which can arise when using Subtypi...&quot;</p> <p><b>New page</b></p><div>In [[software development]], the '''circle-ellipse problem''' (sometimes termed the square-rectangle problem) illustrates several pitfalls which can arise when using [[Subtyping|subtype polymorphism]] in [[Object model|object modelling]].<br /> <br /> The issues are most commonly encountered when using [[object-oriented programming]] (OOP). <br /> <br /> == Description ==<br /> <br /> By definition, this problem is a violation of the [[Liskov substitution principle]], which occurs in the term single responsibility, open-closed, Liskov substitution, interface segregation and dependency inversion ([[SOLID (object-oriented design)|SOLID]]).<br /> <br /> The problem concerns which subtyping or [[Inheritance (object-oriented programming)|inheritance]] relationship should exist between classes which represent circles and ellipses (or, similarly, squares and rectangles).<br /> <br /> More generally, the problem illustrates the difficulties which can occur when a base class contains [[Method (computer programming)|methods]] which mutate an object in a manner which may invalidate a (stronger) invariant found in a derived class, causing the Liskov substitution principle to be violated.<br /> <br /> The existence of the circle-ellipse problem is sometimes used to criticize object-oriented programming. It may also imply that hierarchical taxonomies are difficult to make universal, implying that situational classification systems may be more practical.<br /> <br /> == See also ==<br /> <br /> * [[Inheritance (object-oriented programming)]]<br /> * [[Liskov substitution principle]]<br /> * [[Method (computer programming)]]<br /> * [[Object model]]<br /> * [[SOLID (object-oriented design)]]<br /> * [[Subtyping]]<br /> <br /> == External links ==<br /> <br /> * [https://en.wikipedia.org/wiki/Circle-ellipse_problem Circle-ellipse problem] @ Wikipedia.org <br /> <br /> [[Category:Computer programming]]<br /> [[Category:Computer science]]<br /> [[Category:Computing]]</div>

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