mirror of
https://github.com/Brandon-Rozek/website.git
synced 2024-12-23 07:23:25 +00:00
125 lines
4.7 KiB
HTML
125 lines
4.7 KiB
HTML
<!DOCTYPE html>
|
|
<html>
|
|
<head>
|
|
<meta charset="utf-8" />
|
|
<meta name="author" content="Fredrik Danielsson, http://lostkeys.se">
|
|
<meta name="viewport" content="width=device-width, initial-scale=1.0">
|
|
<meta name="robots" content="noindex" />
|
|
<title>Brandon Rozek</title>
|
|
<link rel="stylesheet" href="themes/bitsandpieces/styles/main.css" type="text/css" />
|
|
<link rel="stylesheet" href="themes/bitsandpieces/styles/highlightjs-github.css" type="text/css" />
|
|
</head>
|
|
<body>
|
|
|
|
<aside class="main-nav">
|
|
<nav>
|
|
<ul>
|
|
<li class="menuitem ">
|
|
<a href="index.html%3Findex.html" data-shortcut="">
|
|
Home
|
|
</a>
|
|
</li>
|
|
<li class="menuitem ">
|
|
<a href="index.html%3Fcourses.html" data-shortcut="">
|
|
Courses
|
|
</a>
|
|
</li>
|
|
<li class="menuitem ">
|
|
<a href="index.html%3Flabaide.html" data-shortcut="">
|
|
Lab Aide
|
|
</a>
|
|
</li>
|
|
<li class="menuitem ">
|
|
<a href="index.html%3Fpresentations.html" data-shortcut="">
|
|
Presentations
|
|
</a>
|
|
</li>
|
|
<li class="menuitem ">
|
|
<a href="index.html%3Fresearch.html" data-shortcut="">
|
|
Research
|
|
</a>
|
|
</li>
|
|
<li class="menuitem ">
|
|
<a href="index.html%3Ftranscript.html" data-shortcut="">
|
|
Transcript
|
|
</a>
|
|
</li>
|
|
</ul>
|
|
</nav>
|
|
</aside>
|
|
<main class="main-content">
|
|
<article class="article">
|
|
<h1>Lecture for October 23</h1>
|
|
<h2>Two-Dimensional Arrays</h2>
|
|
<p>You can think of a two dimensional array as a grid that is organized by rows then columns.</p>
|
|
<p>To declare a two dimensional array do the following</p>
|
|
<pre><code class="language-java">int[][] grid = new int[5][5]; // Declares a 2D array of 5 rows and 5 columns</code></pre>
|
|
<p>You can have as many dimensions as you want. For graphics a 3-dimensional array would render 3D points.</p>
|
|
<p>It doesn't have to be inherently visual though, you can have the n-dimensional array look at the interaction between n different variables. For example, the relationships to different questions in a survey.</p>
|
|
<p>Strings are essentially a char array with extra methods attached. We can imitate an array of strings with a 2D char array.</p>
|
|
<pre><code class="language-java">char[][] helloWorld = new char[5][5];
|
|
hello[0][0] = 'h';
|
|
hello[0][1] = 'e';
|
|
hello[0][2] = 'l';
|
|
hello[0][3] = 'l';
|
|
hello[0][4] = 'o';
|
|
hello[1][0] = 'w';
|
|
hello[1][1] = 'o';
|
|
hello[1][2] = 'r';
|
|
hello[1][3] = 'l';
|
|
hello[1][4] = 'd';
|
|
</code></pre>
|
|
<h2>Nested-For Loops</h2>
|
|
<p>To access the elements in a 2D array, you need to use a nested for-loop. </p>
|
|
<p>Here is how you print out the hello world example above</p>
|
|
<pre><code class="language-java">for (int row = 0; row < helloWorld.length; row++) {
|
|
for (int col = 0; col < helloWorld[row].length; col++) {
|
|
System.out.print(helloWorld[row][col]);
|
|
}
|
|
System.out.print(" ")
|
|
}</code></pre>
|
|
<p>The code above prints out "hello world"</p>
|
|
<h2>2D Arrays in methods</h2>
|
|
<p>You can write a get like method in the following way</p>
|
|
<pre><code class="language-java">public static void get(int[][] array, int row, int col) {
|
|
return array[row][col];
|
|
}</code></pre>
|
|
<p>Arrays in Java are pass by reference not pass by value. Meaning that if you change the array within the method then it will change outside the method.</p>
|
|
<pre><code class="language-java">public static void insert(int[][] array, int row, int col, int numToInsert) {
|
|
array[row][col] = numToInsert;
|
|
}</code></pre>
|
|
<p>To make it not be able to change the array inside the method, use the keyword <code>const</code> inside the method header. To code below will throw a compiler error.</p>
|
|
<pre><code class="language-java">public static void insert(const int[][] array, int row, int col, int numToInsert) {
|
|
array[row][col] = numToInsert; // This line will throw an errror
|
|
}</code></pre>
|
|
</article>
|
|
</main>
|
|
|
|
<script src="themes/bitsandpieces/scripts/highlight.js"></script>
|
|
<script src="themes/bitsandpieces/scripts/mousetrap.min.js"></script>
|
|
<script type="text/x-mathjax-config">
|
|
MathJax.Hub.Config({
|
|
tex2jax: {
|
|
inlineMath: [ ['$','$'], ["\\(","\\)"] ],
|
|
processEscapes: true
|
|
}
|
|
});
|
|
</script>
|
|
|
|
<script type="text/javascript"
|
|
src="http://cdn.mathjax.org/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML">
|
|
</script>
|
|
<script>
|
|
hljs.initHighlightingOnLoad();
|
|
|
|
document.querySelectorAll('.menuitem a').forEach(function(el) {
|
|
if (el.getAttribute('data-shortcut').length > 0) {
|
|
Mousetrap.bind(el.getAttribute('data-shortcut'), function() {
|
|
location.assign(el.getAttribute('href'));
|
|
});
|
|
}
|
|
});
|
|
</script>
|
|
|
|
</body>
|
|
</html>
|