how to create custom post type in wordpress with or without categories

/******slider in dashboard***********/

function my_custom_sliders_posttype(){



$args = array(

'labels'=> array( 'name'=>'sliders',

'singular_name'=> 'slider',

'menu_name'=>'sliders',

'name_admin_bar'=> 'sliders',

'all_items' =>'View all sliders',

'add_new'=> 'Add New sliders' ),

'description' =>"This post type is for sliders",

'public' => true,

'exclude_from_search'=>false,

'publicly_queryable'=> true,

'show_ui' => true,

'show_in_menu'=> true,

'show_in_admin_bar'=> true,

'menu_position'=>6,

'capability_type'=> 'page',

'supports'=> array( 'title', 'editor', 'author', 'thumbnail', 'excerpt',

 ),

'query_var'=>true,





);



register_post_type( "sliders", $args );

}



add_action("init","my_custom_sliders_posttype");



/********************/






IF NEED sub-categories add this code after
add_action("init","my_custom_sliders_posttype");


/**********categories in custom post type  ***********/
register_post_type('blog', $portfolio_args);
$categories_labels = array(

    'label' => 'blog Category',

    'hierarchical' => true,

    'query_var' => true
);
/*********./categories in custom post type  ***********/