How to create an overview of posts with the same tag?

Question

At the bottom of each post, I want to display posts that have the same tag. Based on numerous examples of function doing something similar, I created the function below. I call it from with in the loop from the custom post php that I created. It's called succesfully, but I don't get the list of titles that I expect to get. How do I solve this?

function show_related(){

    $posttags = get_the_tags();
    if ($posttags) {
        $ids = array();
        $relatedpostids = array();
        foreach ($posttags as $tag){
            $id =  $tag -> term_id ;
            $ids[] = $id;
        }
        foreach ($ids as $id){
             $args = array(
                'tag_id' => $id,
            );
            $posts_array = get_posts( $args );
            foreach( $posts_array as $post ) {
                echo the_title();
            }
        }

    }
}

Answer 1

foreach( $posts_array as $post ) {
        echo the_title();
}

I think the problem is you call the_title() without setup_postdata first

If I were you, I'll simply use $post->post_title.

foreach( $posts_array as $post ) {
        echo $post->post_title;
}

This is because you are "get_posts"ing within a loop, and setup_postdata will change global variable $post which is set with the current post's information while The Loop is running.