Few is used in a negative way. It generally refers to hardly any or not many.
A few is used in a positive manner. It generally refers to some, though not many.
The few is used when the following meaning is to be conveyed: All, though not many
Note:- All of the above determiners are followed by a plural noun.
1. Ram is introvert, he has few friends.
2. Few passengers boarded the bus.
3. He is weak in mathematics; he could solve only few problems.
1. He bought a few eggs for the breakfast.
2. He has a few friends.
3. Would you like to have a few candies?
1. The few friends I have are really very helpful.
2. I ate up the few candies I had purchased.
3. The book binder says to the customer, "I can give you the few books I have covered."