Basic things in ABAP with example

Arithmetic expressions in ABAP

In ABAP you can program the following valid arithmetic expressions,

Parameters

In our previous program we have written a set of commands for the arithmetic operations but the input to the variables where hardcoded in the program itself, now what if the user wants to enter the value during runtime?

What if he wants to enter different values each time?

So, we have to write a program which asks input from the user and gives the output.

To get input from user we should use the abap keyword ‘PARAMETERS’.

Ex:

PARAMETERS: input1 type I,

            input2 type I.

 The variable Result should not be defined in parameters because we are not going to get an input to the variable result. (Therefore result should be defined by ‘DATA’)

Data types in abap

Data types

A data type or simply type is a classification for identifying types of data, such as integer, numeric, character etc. that determines the possible values for that type; the operations that can be done on values of that type; the meaning of the data; and the way values of that type can be stored.

Here in abap we can classify them into two groups.

Complete types:

Type for date (D), format YYYYMMDD, LENGTH 8

Type for time (T), format HHMMSS, LENGTH 6

Type for integer (I), LENGTH 4

Type for floating point number (F), LENGTH 8

Type for dynamic length character string

Type for dynamic length byte sequence (HeXadecimal string)

Incomplete types:

Conditional branches and logical expressions

In ABAP you have two ways to execute different sequences of statements.

 As we know about the IF-statement and CASE-statement lets update our previous program (arithmetic calculation) using these conditional statements.

As you can see the keyword ‘PARAMETERS’ is used for getting input from user, we are getting three inputs from the user.

And the output is stored in the variable ‘RESULT’ which is defined by the ‘DATA’ keyword.

Next comes the conditional operator,

IF-statement:

 It checks whether the value in variable ‘SYMBOL’ is one of the symbols described there.

If the symbol is any of these ‘+, - , *, /’ it comes to the next statement (i.e. CASE-statement) or else it executes the ‘ELSE’ part.

CASE-statement:

Depending upon the symbol the case statement is executed i.e. when the symbol is ‘+’ it executes the addition and when the symbol contains the value ‘-‘ the operation subtraction is performed.

Whenever an operation is performed the result is stored in the variable ‘RESULT’, and at the end of the CASE-statement we are printing the result in the screen.

Now, come back to the IF-statement (line 16).

If the symbol contains value which is not defined there, it comes to the ELSE part.

The ELSE part contains the code for writing an error ‘symbol is not defined in the program’.

In line 16 the Relational operator OR is described after every condition.

See how the compiler reads the program.

Line16 -> Checks whether the value in symbol is ‘+’ OR‘-‘ OR‘*’  OR ‘/’ .

(If the value in symbol is any of the following above Line18 is executed or else Line 30 is executed)