Get cart total return 0

Hi,
i’m trying to display the cart total in the cart popup.
Also im using wc_cart_totals_order_total_html() function.
i noticed that the result is 0.

after digging this issue i saw that when im adding products to cart, calculate_totals() function is called but it not calculate the total because this line:

// Only calculate the grand total + shipping if on the cart/checkout
if ( is_checkout() || is_cart() || defined( ‘WOOCOMMERCE_CHECKOUT’ ) || defined( ‘WOOCOMMERCE_CART’ ) ) {

what i do is define WOOCOMMERCE_CHECKOUT to true.

its ok? and why this conditon need for?

Thanks