LOOP AT SCREEN.
...
ENDLOOP.
Effect
This is a short form of the statement
LOOP AT SCREEN INTO screen.
...
ENDLOOP.
The short form uses a structure with the name screen implicitly
instead of an explicitly declared work area wa . This is either
the obsolete predefined structure
screen or a structure declared in the current context called
screen , which must have the data type
SCREEN .
Notes
Use the long form with an explicitly declared
work area instead of the short form.
The short form of the statement LOOP AT SCREEN behaves like the
statement LOOP in a loop across an
internal table with a header line , where
the predefined structure is used as the header line.
Documentation extract taken from SAP system, � Copyright SAP AG. All rights reserved