<!DOCTYPE html> <html> <head> <meta charset="utf-8" /> <meta name="author" content="Brandon Rozek"> <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 January 30</h1> <h2>Random Number Generator</h2> <p>One of the ways you can do a random number generator is through this method:</p> <p>Import a class called random </p> <pre><code class="language-java">import java.util.Random;</code></pre> <p>Then you need to create a <code>Random</code> object</p> <pre><code class="language-java">Random rand = new Random();</code></pre> <p>After this you can call the <code>nextInt()</code> method to get a random number between 0 and $2^{32}$</p> <pre><code class="language-java">int randInt = rand.nextInt();</code></pre> <p>If you don't want a random number between 0 and $2^{32}$ but instead to another maximum value, then you can call the <code>nextInt</code> method inserting the max integer as a parameter.</p> <p>Random Integer from 0-10 (not including 10)</p> <pre><code class="language-java">int randInt2 = rand.nextInt(10);</code></pre> <h2>Output</h2> <p>We have already encountered <code>System.out.println</code> and <code>System.out.print</code> but let us go over the differences again.</p> <p><code>System.out.println()</code> prints the contents inside the parenthesis and appends a newline character afterwards so that the next output is on a new line</p> <p><code>System.out.print()</code> prints the contents inside the parenthesis and does not output a newline character</p> <h3>Formatting Output</h3> <p>If you want more control on how your output is displayed, it is recommended that you use <code>System.out.printf</code> to format your output</p> <p>First, you need to specify your type using the % instruction</p> <ul> <li>d for integer</li> <li>f for decimal</li> </ul> <p>Example:</p> <pre><code class="language-java">int sum = 50; System.out.printf("Total = %d", sum);</code></pre> <p>This outputs </p> <pre><code class="language-reS">Total = 50</code></pre> <p>Notice here that there is no concatenation required like the previous two methods, instead you insert the variables as parameters</p> <p>Let us deconstruct the % instruction</p> <p>% <strong> </strong> . <strong> </strong></p> <p>The first underline is the + - 0 space (sometimes we want to pad the money with zeros)</p> <p>The second underline is the width of the text</p> <p>The third underline is the number of decimal places</p> <p>The the final underline is the specifier <code>f</code> for decimal and <code>d</code> for integer</p> <p><u>Example</u></p> <pre><code class="language-java">double amount = 0.5; System.out.printf("Total Due: %0.2f")</code></pre> <p>This outputs</p> <pre><code class="language-reStructuredText">Total Due: 0.50</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>