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136 lines
3.2 KiB
Markdown
136 lines
3.2 KiB
Markdown
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---
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id: 2241
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title: Obtaining Command Line Input in Java
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date: 2017-08-28T17:37:59+00:00
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author: Brandon Rozek
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layout: post
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guid: https://brandonrozek.com/?p=2241
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permalink: /2017/08/obtaining-command-line-input-java/
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medium_post:
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- 'O:11:"Medium_Post":11:{s:16:"author_image_url";N;s:10:"author_url";N;s:11:"byline_name";N;s:12:"byline_email";N;s:10:"cross_link";N;s:2:"id";N;s:21:"follower_notification";N;s:7:"license";N;s:14:"publication_id";N;s:6:"status";N;s:3:"url";N;}'
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mf2_syndicate-to:
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- 'a:1:{i:0;s:4:"none";}'
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mf2_cite:
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- 'a:4:{s:9:"published";s:25:"0000-01-01T00:00:00+00:00";s:7:"updated";s:25:"0000-01-01T00:00:00+00:00";s:8:"category";a:1:{i:0;s:0:"";}s:6:"author";a:0:{}}'
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tumblr_post_id:
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- "164717769554"
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mf2_mp-syndicate-to:
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- 'a:1:{i:0;s:4:"none";}'
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kind:
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- note
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---
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To obtain console input for your program you can use the <code class="language-java">Scanner</code> class
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First import the relevant library
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<pre class="language-java"><code class="language-java">
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import java.util.Scanner;
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</code></pre>
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Then create a variable to hold the <code class="language-java">Scanner</code> object
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<pre class="language-java"><code class="language-java">
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Scanner input;
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input = new Scanner(System.in);
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</code></pre>
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Inside the parenthesis, the <code class="language-java">Scanner</code> binds to the System input which is by default the console
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The new varible <code class="language-java">input</code> now has the ability to obtain input from the console. To do so, use any of the following methods
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<table class="tg">
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<tr>
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<th class="tg-yw4l">
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Method
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</th>
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<th class="tg-yw4l">
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What it Returns
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</th>
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</tr>
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<tr>
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<td class="tg-yw4l">
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next()
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</td>
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<td class="tg-yw4l">
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The next space seperated string from the console
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</td>
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</tr>
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<tr>
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<td class="tg-yw4l">
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nextInt()
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</td>
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<td class="tg-yw4l">
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An integer if it exists from the console
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</td>
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</tr>
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<tr>
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<td class="tg-yw4l">
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nextDouble()
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</td>
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<td class="tg-yw4l">
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A double if it exists from the console
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</td>
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</tr>
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<tr>
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<td class="tg-yw4l">
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nextFloat()
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</td>
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<td class="tg-yw4l">
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A float if it exists from the console
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</td>
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</tr>
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<tr>
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<td class="tg-yw4l">
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nextLine()
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</td>
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<td class="tg-yw4l">
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A string up to the next newline character from the console
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</td>
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</tr>
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<tr>
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<td class="tg-yw4l">
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hasNext()
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</td>
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<td class="tg-yw4l">
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Returns true if there is another token
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</td>
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</tr>
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<tr>
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<td class="tg-yw4l">
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close()
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</td>
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<td class="tg-yw4l">
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Unbinds the Scanner from the console
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</td>
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</tr>
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</table>
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Here is an example program where we get the user’s first name
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<pre class="language-java"><code class="language-java">
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import java.util.Scanner;
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public class GetName {
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public static void main(String[] args) {
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Scanner input = new Scanner(System.in);
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System.out.print("Please enter your name: ");
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String firstName = input.next();
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System.out.println("Your first name is " + firstName);
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}
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}
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</code></pre>
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