Beer and cider are different from each other because they come from different sources. Beer comes from malted barley while cider comes from apple juice. Take note that cider can be alcoholic or non-alcoholic depending on how it will be prepared. Beer is known to be an alcoholic beverage but most beers only have small alcohol content. Beer is prepared by fermenting malted barley.
They can be flavored differently depending on the hops that will be chosen. Beer cannot be considered as cider and vice versa because the only similar thing about these two beverages is they have to undergo fermentation before they become the way that they are.