Visual Basic 2005 in a Nutshell, Third Edition

86

|

Chapter 5: Operators

This is the Title of the Book, eMatter Edition

Copyright © 2006 O’Reilly & Associates, Inc. All rights reserved.

understandings of addition and subtraction were reversed. However, such prac-

tices will make the code more difficult to understand and debug.

For further details about operator overloading, see the “Operator Statement”

entry in Chapter 12.

Operator Precedence

If you include more than one operator in a single line of code, you need to know

the order in which VB will evaluate them. Otherwise, the results may be

completely different from what you intended. For instance, the following

statement:

x = 5 + 3 * 7

could be interpreted as:

x = (5 + 3) * 7 ' --> 56

or as:

x = 5 + (3 * 7) ' --> 26

The rule that defines the order in which a language processes operators is known

as the order of precedence. If the order of precedence results in operations being

evaluated in an order other than the intended one, you can explicitly override the

order of precedence through the use of parentheses. Indeed, complex (or even

relatively simple) expressions should include parentheses to avoid any compiler

misinterpretation or human confusion. (By the way, the example, once paren-

theses are removed, evaluates to 26.)

When multiple operators appear at the same level of evaluation (that is, they are

not subgrouped with parentheses), they are processed in a specific order of prece-

dence. In