How to use a variable as a function name?

<?php
$numcpost = of_get_option('how_many_custom_posts');

do {

    add_action( 'init', 'register_cpt_mdframework_price', $numcpost );
    --$numcpost;

} while ( $numcpost > 0 );

function register_cpt_mdframework_price( $numcpost ) {

    $singcpost = of_get_option('custom_posts_name_s_n'.$numcpost.'');
    $plurcpost = of_get_option('custom_posts_name_p_n'.$numcpost.'');
    $desccpost = of_get_option('custom_posts_name_d_n'.$numcpost.'');
    $imgcpost  = of_get_option('custom_posts_name_i_n'.$numcpost.'');

    $labels = array();
        // labels for $numcpost = 1
    $labels[1] = array(/*typo was here*/
            'name' => _x( $plurcpost, 'mdframework_custom_created_post'.$numcpost.'' ),
            'singular_name' => _x( $singcpost, 'mdframework_custom_created_post'.$numcpost.'' ),
            'add_new' => _x( 'Add New', 'mdframework_custom_created_post'.$numcpost.'' ),
    );

        // labels for $numcpost = 2
    $labels[2] = array(
        // ...
    );

    $args = array();

        // args for $numcpost = 1
    $args[1] = array(
            'labels' => $labels[1],
            'hierarchical' => true,
            'description' => $desccpost,    
    );

        // args for $numbercpost = 2
    $args[2] = array(
            'labels' => $labels[2]
        // ...
    );

    register_post_type( 'mdframework_custom_created_post_'.$numcpost, $args[$numcpost] );
}

Use multidimensional arrays. Simple, isn’t it?