Why is ++xy not considered a syntax error?

[Emilio]

Dim xy As Integer
xy = 1
MsgBox(++xy)

Why is ++xy not considered a syntax error. Does it do anything?
(it doesn't increment xy, as c# programmers might expect)

 

[Herfried K. Wagner [MVP]]

Dim xy As Integer
xy = 1
MsgBox(++xy)

Why is ++xy not considered a syntax error. Does it do anything?
(it doesn't increment xy, as c# programmers might expect)

'++' is treated as sign, '-+1' will result in -1, '--1' will result in 1.

 

[Jay B. Harlow [MVP - Outlook]]

Emilio,
Because plus (+) can be either a unary or a binary operator, you simply
applied the unary plus operator to xy twice. In other words you did:

MsgBox(+(+(xy)))

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vbls7/html/vblrfVBSpec11_4_1.asp

"The unary plus operator results in the value of the operand"

Hope this helps
Jay

 

[Jay B. Harlow [MVP - Outlook]]

Emilio,
I should add, that Paul Vick's "The Visual Basic .NET Programming Language"
from Addison Wesley is a good (right size, right content) desk reference to
the VB.NET language itself. Paul's book covers just the language, not the
framework.

Hope this helps
Jay

 

[Emilio]

Emilio,
I should add, that Paul Vick's "The Visual Basic .NET Programming Language"
from Addison Wesley is a good (right size, right content) desk reference to
the VB.NET language itself. Paul's book covers just the language, not the
framework.

O.k. thanks, I know the language by en large, you don't normally
stumble on those things unless you are trying to convert from c# to
vb. At the moment I can't see anything which is better in c# than
it is in vb, so I'll stay with vb.