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Line 19: == The J language == A frequent reaction when one first encounters a J program is often something along the lines of "that's cheating". The thought here is that the problem could not possibly be that simple, so --— instead --— the issue must be that J was specifically designed to tackle that problem. The flip side of this issue is that J is a dialect of APL --— a language whose development started in the 1950s and which was implemented in the early 1960s. And, originally, APL was designed as a language to describe computer architecture. The implementation as a programming language was motivated by its original successes in documenting computer hardware and instructions, and the relative simplicity of its concepts. See also https://github.com/cratelyn/j for some reflection on some of the linguistic character of J. == Introduction == Line 33 ⟶ 35: Object-module and imperative techniques are supported, but not required. The J programming language was designed and developed by [~~http~~[wp:~~//en.wikipedia.org/wiki/Kenneth_E._Iverson~~ Ken Iverson]] and Roger Hui. It is a closely related successor to [[APL]], also by Iverson which itself was a successor to the notation Ken Iverson used to teach his classes about computers in the 1950s. <br clear="all"/> Line 49 ⟶ 51: For example, the phrase <code>(+/ % #)</code> finds the average of a list of numbers. <syntaxhighlight lang="j"> ~~<lang J>~~ (+/ % #) 1 2 3 ~~2</lang>~~ 2 </syntaxhighlight> To understand how this works, you might try working with simpler sentences and their variations. <syntaxhighlight lang="j"> ~~<lang J>~~ +/ 1 2 3 6 +/4 5 6 Line 67 ⟶ 72: 5 (+/ % #) 4 5 6 5 ~~5</lang>~~ </syntaxhighlight> By themselves, these experiments mean nothing, but if you know that +/ was finding the sum of a list and # was finding the length of a list and that % was dividing the two quantities (and looks almost like one of the old school division symbols) then these experiments might help confirm that you have understood things properly. == Some ~~Perspective~~perspective == If you wish to use J you will also have to learn a few grammatical rules (J's parser has [http://www.jsoftware.com/help/dictionary/dicte.htm 9 reduction rules] and "shift" and "accept" - the above examples use four of those rules). J verbs have two definitions - a single argument "monadic" definition and a two argument "dyadic" definition. Line 97 ⟶ 103: Discussion of the goals of the J community on RC and general guidelines for presenting J solutions takes place at [[J/HouseStyle\|House Style]]. == Jedi on RosettaCode ==