Java - Arrays

Exercises, examples and other material relating to training module J705. This topic is presented on public courses Learning to Program in Java, Java Bootcamp, Java Programming for the Web

A regular variable can hold one piece of information, but an array can hold more than one. Arrays are declared to hold a number of elements, and data is then written to and read from each element based on its position number.

Articles and tips on this subject		updated
4428	Using the lead - passing arrays and other collections in Java If you're taking the dog for a walk, it's much more lightweight to simply take the lead and have the dog follow than to actually carry the dog. And if you're passing a whole collection of data into a function, it's much more lightweight to pass in the address or reference to the collection than to ...	2015-02-17
4413	Binomial Coefficient (Pascal Triangle) objects in Java An exercise on our Java course from which our delegates gain a lot of appreciation is the one in which I ask them to set up an array of arrays containing Pascal's Triangle of Binomial Coefficients. It sounds mighty complex, but I explain it on the board and it comes down to just defining the arrays ...	2015-02-04
4347	Arrays in Java - an introduction for newcomers In Java, arrays are objects but with some extra syntax which gives you additional ways to access them, for example using a traditional subscripting notation. From the Java Course I am running this week, an example written in front of my delegates is [here]. Setting up an array ... float ...	2014-12-09
3118	Arrays of arrays - or 2D arrays. How to program tables. It's shorthand when you're learning a new programming language to ask "how does it handle multiple dimension arrays" ... but in practise very few languages actually support true multidimensional arrays these days, and in those which do you might be well advised to use an alternative that's more flexible. What ...	2011-01-03
3039	Fresh Paint - Java Arrays I've just applied a coat of fresh paint to some of our Java examples - Arrays in Java - and added the refurbished examples on the web site. The great news is that the old code just worked (I love compatability) but I have much improved the comments. 1. [code] - a 2 dimensional array (or strictly speaking ...	2010-11-09
3038	Setting up individual variables, and arrays, in Java - some commented examples In Java, variables must be defined before they have an initial value assigned to them, and they must have an initial value assigned to them before the value thay contain is used; there's no automatic assumption that a new name is a variable, nor is there an assumption made of what type of data a variable ...	2010-11-09
2648	Java arrays - are they true arrays or not? Java's arrays are "true" arrays, in that they occupy sequential memory locations in which they are looked up by position number, so that access can be very fast. But that does mean that once an array has been defined to be a certain size, it cannot be resized in situ. Fortunately, Java is a dynamically ...	2010-03-03
1614	When an array is not an array An array, I was taught, is a sequential series of memory locations in which values of some type are stored. In an array, each of the memory locations is the same size (number of bytes). And so, as I was taught, arrays can be used very efficiently using pointer arithmetic, BUT they need to: a) Be defined ...	2008-04-19
1498	Java is a dynamic language .... (and comparison) Many older programmers are used to setting up an array of a fixed size and saying "that's fixed" ... for the duration of the program, if not for all time until the application is recompiled. Languages such as C gave us malloc, calloc and realloc (and things have progress on somewhat in C++) to let us ...	2008-01-09
1497	Training Season Starts again! I'm glad that our business isn't heavily seasonal - tourist places like Longleat have a heavy summer and a barren winter, and The Christmas Shop must, surely, be heading for a quiet few months. But we are - slightly - seasonal; we have a quiet three weeks where no-one wants to learn Perl or PHP (or ...	2008-01-07

Examples from our training material

A350.java	Array - setting up, filling, looking for highest and lowest values
A365.java	Array - length, initialise throughout, arrays or strings
Arr1.java	First Array in Java
Arx.java	Array demonstration
Ax1.java	Passing arrays by their references
Bowerhill.java	Dynamic Array sizing (multidimensional)
Charlton.java	Setting up and using array of arrays
Cornet.java	Sample exercise answer (2)
Flute.java	Sample exercise answer (1)
Gurdy.java	Pascal's triangle using dynamic arrays
Hurdy.java	Pascal's traingle using a two dimensional array
PascalAsObject.java	Pascal Triangle as Object
Weekend.java	Array of Objects
Wilsford.java	Two Dimensional non-rectangular Array
compton.java	Array initialisation
rowby.java	Dynamic use of arrays
rushall.java	Two dimensional array
upavon.java	Array Manipulation

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Studying Java in Oxford

Background information

Some modules are available for download as a sample of our material or under an Open Training Notes License for free download from [here].

Topics covered in this module

Definition and declaration.
Use.
Array manipulation and replacement.
Multidimensional arrays.
Arrays of Objects.

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