There are mainly two type of Accounting System:

Cash System– Under this system all transaction are recorded only on cash basis i.e. when cash is being received or paid. e.g. You purchased goods for your business on 24th March 2014 but payment is made on 01 st April 2014  . then txn will be recorded in the books of next year i.e. in F.Y. 2014-15.

Accrual/Mercantile System-Under this system all transaction are recorded  on accrual basis i.e. as and when they occur e.g. You purchased goods for your business on 24th March 2014 but payment is made on 01 st April 2014  . then txn will be recorded in the books of current year.i.e. on 24th March 2014 for F.Y. 2013-14