Officers are trained not to show the results on the side of the road, since their next move is to put you in cuffs and they want a smooth transition from blow to cuffs. Sometimes they tell you after you are in cuffs and in the car, or even later. They are not required to tell you the results.
At the station or wherever they conduct the evidential breath test, they should tell you, but are not required to do so. We can often get the results from DMV before Court, since DMV will usually have that information before your arraignment date.
Being arrested for a DUI in California is a traumatic experience, and unfortunately not all cops treat you with respect.