it would be difficult to say without offering more information. Do you think your battery just died? Was it acting up in any way before completely dying on you? Did it stall out and not start again? Do you even know if it was acting up before this happened? You'd need to give more information before getting good answers that may actually help you out...
if it cranks it is not your battery or starter. If it does not turn over with a good charged battery, then it is your starter that's bad. And you should go into more detail about what it does or does not do . to be able to help you.