/// <summary>
/// Sepete kupon tanımlame methodu
/// </summary>
/// <param name="coupon">Kupon</param>
public void ApplyCoupon(ICoupon coupon)
{
var nPrice = coupon.CalculateCoupon(CartPrice);
if (nPrice != CartPrice)
{
_UsedCoupon = coupon;
_discountCoupon = CartPrice - nPrice;
CartPrice = CartPrice - _discountCoupon;
}
}
