Show "Stock Out" if all variations are stock out.

function.php

function wc_show_variable_product_stock_out()
{
	global $product;
	if( $product->is_type( 'variable' ) )
	{
		$args = array(
			'post_type'     => 'product_variation',
			'post_status'   => array( 'private', 'publish' ),
			'numberposts'   => -1,
			'orderby'       => 'menu_order',
			'order'         => 'asc',
			'post_parent'   => $product->id // $post->ID 
			);
		$variations = get_posts( $args );

		$is_stock_out = true; 
		foreach ($variations as $key => $variation_post)
		{
			$product1 	= wc_get_product( $variation_post->ID );
			$stock 		= $product1->get_total_stock();

			if($product1->is_in_stock() && $stock > 0)
			{
				$is_stock_out = false;
			}
		}
		if($is_stock_out)
		{
			?>
			<p class="stock out-of-stock">Sold out</p>
			<?php
		}
	}
}
add_action("woocommerce_single_product_summary", "wc_show_variable_product_stock_out", 10);