Dogs and wolves (like many other carnivorous animals) can make their own vitamin C in the body and do not need to consume it. They don't need much in the way of carbs.
If you are talking ingestion of plant matter, dogs and wolves which are their closest analogues (genetically so close they can interbreed), the answer is that they will occasionally eat some berries and nibble on shoots (particularly grass) in the spring when they are full of sugars.
They will also eat the stomach contents of herbivorous prey animals.
Carbohydrates are technically the only macronutrient humans can survive without consuming (not that I fancy it).