Here we are going to write Schedulable batch & batch stateful program. We will also see how to use cron in batch. In this example we will simply update the account information which will run on 8.00 PM everyday. We have written a seperate program for Schedulable batch but we can also include that in same batch class. We have taken "integer i" just to take the state of batch everytime time it runs in chunks. You can see the output value of  "i" in debug console log.