You can combine
several logical expressions together in one single expression by using the
logical link operators **AND**and **OR**: To
negate the result of a logical expression, you can precede it with the
**NOT** operator.

**NOT** takes priority over **AND**, and **AND**takes priority over **OR**. However, you can use any combination of parentheses
to specify the processing sequence. As in mathematical expressions, ABAP interprets
each parenthesis as a separate word. You must therefore leave at least one space before
and after each one.

ABAP processes
logical expressions from left to right. If it recognizes one of the component expressions as
true or false, it does not perform the remaining comparisons or checks in this
component. This means that you
can improve performance by organizing logical expressions in such a way that
you place comparisons which are often false at the beginning of an
**AND**chain and expensive comparisons, such as
searches for character strings, at the end.

**REPORT
demo_log_expr_connected.**

**DATA:
f TYPE f VALUE '100.00',
n(3) TYPE n VALUE '123',
c(3) TYPE c VALUE '456'.**

**WRITE 'The following
logical expression is true:'.**

**IF ( c LT n ) AND ( n GT
f ).
WRITE: / '(',c,'lt',n,') AND (',n,'gt',f,')'.
ELSE.
WRITE: / '(',c,'ge',n,') OR (',n,'le',f,')'.
ENDIF.**

The list output is:

The following logical expression is true:

( 456 ge 123 ) OR ( 123 le 1.000000000000000E+02 )

The logical
expression in the **IF** statement is true, and the inverted expression is
displayed.