Parent Page and Sub Pages Conditional Content Display

gistfile1.php

global $post;

if (is_page()) {
    if ($post->post_parent) {
        echo '<h1>Child page: ' . $post->post_title . '</h1>';
        echo '<p>You can display content specific to child pages here.</p>';
    } else {
        echo '<h1>Page parent: ' . $post->post_title . '</h1>';
        echo '<p>You can display content specific to parent pages here.</p>';
    }
} else {
    echo '<p>You can handle other content types or scenarios here.</p>';
}