What are the types of processing blocks? | SAP-ABAP

 ABAP programs are made up of processing block which is modular in nature.
There are two types of processing blocks in ABAP:
=>    Processing blocks which are called from outside the program with the help of ABAP runtime environment.
It helps in normal execution of ABAP programs.
a.    Event Blocks
b.    Dialog Modules
=>    Processing blocks which are called from ABAP statements in ABAP programs.
a.    Subroutines
b.   Functional modules
c.   Methods.