Much as a blueprint or architect's drawing defines what an item or a building will look like once it has been constructed, a class defines what an object will look like when it is created. It defines, for example, what the ''methods'' will do and what the ''member'' variables will be.
Exception encountered, of type "Error"
[cb18c0de] /index.php/Special:MobileDiff/4035 Error from line 434 of /var/www/techotopia/includes/diff/DairikiDiff.php: Call to undefined function each()
Backtrace:
#0 /var/www/techotopia/includes/diff/DairikiDiff.php(544): DiffEngine->diag()
#1 /var/www/techotopia/includes/diff/DairikiDiff.php(344): DiffEngine->compareSeq()
#2 /var/www/techotopia/includes/diff/DairikiDiff.php(227): DiffEngine->diffLocal()
#3 /var/www/techotopia/includes/diff/DairikiDiff.php(721): DiffEngine->diff()
#4 /var/www/techotopia/includes/diff/DairikiDiff.php(859): Diff->__construct()
#5 /var/www/techotopia/includes/diff/DairikiDiff.php(980): MappedDiff->__construct()
#6 /var/www/techotopia/extensions/MobileFrontend/includes/diff/InlineDiffFormatter.php(99): WordLevelDiff->__construct()
#7 /var/www/techotopia/includes/diff/DiffFormatter.php(140): InlineDiffFormatter->changed()
#8 /var/www/techotopia/includes/diff/DiffFormatter.php(82): DiffFormatter->block()
#9 /var/www/techotopia/extensions/MobileFrontend/includes/diff/InlineDifferenceEngine.php(117): DiffFormatter->format()
#10 /var/www/techotopia/includes/diff/DifferenceEngine.php(797): InlineDifferenceEngine->generateTextDiffBody()
#11 /var/www/techotopia/includes/diff/DifferenceEngine.php(728): DifferenceEngine->generateContentDiffBody()
#12 /var/www/techotopia/extensions/MobileFrontend/includes/specials/SpecialMobileDiff.php(241): DifferenceEngine->getDiffBody()
#13 /var/www/techotopia/extensions/MobileFrontend/includes/specials/SpecialMobileDiff.php(135): SpecialMobileDiff->showDiff()
#14 /var/www/techotopia/extensions/MobileFrontend/includes/specials/MobileSpecialPage.php(53): SpecialMobileDiff->executeWhenAvailable()
#15 /var/www/techotopia/includes/specialpage/SpecialPage.php(384): MobileSpecialPage->execute()
#16 /var/www/techotopia/includes/specialpage/SpecialPageFactory.php(553): SpecialPage->run()
#17 /var/www/techotopia/includes/MediaWiki.php(281): SpecialPageFactory::executePath()
#18 /var/www/techotopia/includes/MediaWiki.php(714): MediaWiki->performRequest()
#19 /var/www/techotopia/includes/MediaWiki.php(508): MediaWiki->main()
#20 /var/www/techotopia/index.php(41): MediaWiki->run()
#21 {main}