Do you like candy?
Would you like some candy?
Do you like walking?
Would you like to go for a walk?
What is the difference? And are they the same or not? Do they any use in different situations?
They are not the same:
Do you like is used to ask if someone generally enjoys or is partial to something.
Would you like is a politer way of asking "do you want" when offering something. In English, as in many languages, the verb "want" is considered very direct, and the conditional serves to soften it a bit.
The other answers are not incorrect. They are technically correct, which is the best kind of correct.
However, there are cases that can blur the lines between the two. Consider the following instances:
Bob: Man, I'm starving.
Alice: Do you like pizza?
In this case, Alice is asking "do you like" but because Bob has already said he's looking to have some food, it is implied that Alice has some pizza to alleviate Bob's hunger.
This can also be unsolicited, such as
Alice grabs plate of nachos and motions them towards Bob
Alice: Do you like nachos?
Here Alice still has something to offer Bob, using "Do you like". There's a number of replies. A simple "no" would be inappropriate: Bob should indicate whether he is stating he doesn't like nachos, or whether he just doesn't want any right now.
These are both technically incorrect on Alice's part. (Get it together, Alice!) However, they're common enough that I wouldn't consider them fringe cases.
Would you like is hypothetical. it could be an offer but not necessarely, it refers to something that you think you will like : would you like to be rich ? would you like some food?
Do you like is more concrete and based on knowledge. Do you like food? do you like to be rich? the person that asks you the question assumes you have experience in this field.