how to not show plugin in admin area

I’m just getting started with wordpress development. I’m trying to create a simple plugin that show results from a db in a table. I can do this, but I’m having trouble with the plugin showing at the top of the admin pages. I’m not sure why it does this.

my plugin function:

add_action('init','hello_world');
    function hello_world()
    {

        global $wpdb;
        $query = "Select ID, post_title
                  From $wpdb->posts Limit 0, 10";
        $results = $wpdb->get_results($query, ARRAY_A);

        echo "<div class=\"datagrid\"><table>";
        echo "<thead><tr><th>header</th><th>header</th><th>header</th><th>header</th></tr></thead>";
        echo "<tfoot>
                    <tr>
                    <td colspan=\"4\">
                        <div id=\"paging\">
                            <ul>
                                <li>
                                    <a href=\"#\"><span>Previous</span></a>
                                </li>
                                <li>
                                    <a href=\"#\" class=\"active\"><span>1</span></a>
                                </li>
                                <li>
                                    <a href=\"#\"><span>2</span></a>
                                </li>
                                <li>
                                    <a href=\"#\"><span>3</span></a>
                                </li>
                                <li>
                                    <a href=\"#\"><span>4</span></a>
                                </li>
                                <li>
                                    <a href=\"#\"><span>5</span></a>
                                </li>
                                <li>
                                    <a href=\"#\"><span>Next</span></a>
                                 </li>
                            </ul>
                        </div>
                    </tr>
                </tfoot>";
        echo "<tbody>";
        $i = 0;
        while($i < 10)
        {
            foreach ($results as $item)
            {
                $postID = $item['ID'];
                $postTitle = $item['post_title'];

                echo "<tr class=\"alt\">";
                echo "<td>" .$postID."</td>";
                echo "<td>".$postTitle."</td>";
                echo "</tr>";
                $i++;
            }
        }

        echo "</tbody>";
        echo "</table></div>";
    }

calling in index.php

    <?php
        if(is_admin())
        {

        }
        else
        {
            if(function_exists('hello_world')) {
                echo "<div>";
                hello_world();
                echo "</div>";
            }
        }
    ?>

how can I prevent this from showing in the admin section?

To complement @s_ha_dum’s answer: If you just want to offer a function to be used in a theme, make it a custom action.

Sample:

add_action( 'call_hello_world', 'hello_world' );

Now, in a theme, the author can call your function with …

do_action( 'call_hello_world' );

… and the function will print its content only where the author needs it.

This has at least three advantages:

• You can disable the plugin anytime, and nothing will break. If there is no callback for an action, nothing will happen.
• You don’t have to check with function_exists(), which is always … ugly.
• Another plugin can use the same action, or it can replace your callback.

Here is a sample plugin:

<?php
/*
 * Plugin Name: Custom Action
 */

add_action( 'call_hello_world', 'hello_world' );

/**
 * Demo function.
 *
 * Usage:
 * do_action( 'call_hello_world' );
 *
 * @wp-hook call_hello_world
 * @return void
 */
function hello_world()
{
    print '<h1>Hello World!</h1>';
}

// static class method
add_action( 'call_static_method', array ( 'Demo_Class', 'static_method' );


// dynamic class method
$demo = new Demo_Class;
add_action( 'call_dynamic_method', array ( $demo, 'dynamic_method' );

class Demo_Class
{
    public static function static_method()
    {
        print 'I was called statically.';
    }

    public function dynamic_method()
    {
        print 'I was called with an instance.';
    }
}

Install, activate, and use the do_action() in a theme as often as you need it.