Introduction (Lesson -1)

ABAP stands for – Advanced Business Application Programming.It is  a programming language for developing applications for the SAP R/3 system.
The latest version of ABAP is  called  ABAP Objects and supports object-oriented programming. SAP will run applications written using ABAP/4, the earlier ABAP version, as well as applications using ABAP Objects.
Without further adieu , lets dive into ABAP.
Note, this tutorial will not go into extensive details on ABAP language constructs (which become very boring to read ) but quickly introduce key concepts to get you started so you can focus your attention on more important topics.

Data Types

Syntax to declare a variable in ABAP -

DATA Variable_Name Type Variable_Type.

Example:

DATA employee_number Type I.

The following is a list of Data Types supported by ABAP

Data Type	Initial field length	Valid field length		Initial value	Meaning
Numeric types
I	4		4	0	Integer (whole number)
F	8		8	0	Floating point number
P	8		1 – 16	0	Packed number
Character types
C	1		1 – 65535	‘ … ‘	Text field(alphanumeric characters)
D	8		8	’00000000′	Date field(Format: YYYYMMDD)
N	1		1 – 65535	’0 … 0′	Numeric text field(numeric characters)
T	6		6	’000000′	Time field(format: HHMMSS)
Hexadecimal type
X	1		1 – 65535	X’0 … 0′	Hexadecimal field

Processing Data
- Assigning Values

a=16.
move 16 to a.
write a to b.

- Arithmetic Operations

compute a = a*100.

Control Statements

Following control statements can be used -
- If … EndIf Loop

if [not] exp [ and / or [not] exp ].
……..
[elseif exp.
.......] [else.
.......] Endif.

- Case statement

Case variable.
when value1.
………
when value2.
………
[ when others.
.........] Endcase.
Do.

-While loop

While <logical expression>.

…..

…..

Endwhile.

- Do loop

Do <n> times.

…..

…..

Enddo.

Logical Operator

A list of logical operators

• GE or >=
• GT or >
• LE or <=
• LT or <
• EQ or =
• NE or <>

ABAP/4 Editor

Finally , here is where you will spent most of your time as a developer creating / modifying programs. Transaction SE38