Logic

sucram

Shut the f... up.

Ego non sum semper iustus tamen Ego sum nunquam nefas!

Timothy Byrd

So if I have this straight, in your example:

if(UsernameTextBox.Text == "Manager" & PasswordTextBox.Text == "Maintenance")

because both arguments are boolean, the '&' is effectively acting just like a '&&' except for being trivially less efficient because it is always doing both of the string compares. I know in this case you were merely quoting previous post using '&', but even if the non-short-circuit behaviour would be useful sometime, I'd avoid it because it just looks wrong to me. We're in a mixed C++/C# environment here, and I have to be on the lookout for misused '&'s in the code as it is. Allowing for false positives is not in the cards here. That said, I think you got a raw deal.

Rob Grainger

And quite rightly so. While for booleans, & can work as a logical operator, in all other cases it is bitwise. For consistency, use a single operatopr to represent logical operators throughout, the C# designers (C really) chose && for this purpose. It may work, but its obfuscated, and should be rejected or corrected by any reasonable code review, regardless of any appeals you make to technical documentation.

Timothy Byrd

Rob, I think the problem is that you are assuming human beings are rational/reasonable. Where I am currently, I have to fill out a form and get authorization to fix a simple memory leak. The code base is several million lines of C++, suffering from 20 years of technical debt. Since I already have a reputation for being "too critical about code quality" which causes my input to get knocked down a level or two, I have to bite my tongue a lot. It's a grand learning experience, but I'll be glad when I figure out what the lesson is!

Firo Atrum Ventus

The lesson : Never start a fight in the Hall of Shame :laugh:

hairy_hats

Fabio V Silva wrote:

If you're working as C# developer I think you should RTFM.

No need to be impolite.

Lost User

'AND' in VB is not equivalent to '&' in C#, but equivalent '&&'. this is applicable for OR also... Only difference is 'AND' is not short circuited where '&&' is short circuited. To achieve short circuited and VB require explicit usage of 'AND ALSO'

agolddog

But nobody here can understand why I continue to suggest we move from VB to C#. Of course we want the default behavior to be as inefficient as possible!

dchrno

In your example it's a waste of CPU cycles not to short circuit using &&. The exception is if you have somehow overloaded the & operator, or have logic in your Text property that needs to be evaluated every time.

Jason Christian

http://msdn.microsoft.com/en-us/library/aa691306%28v=vs.71%29.aspx[^] This (from Microsoft) includes & and | in the logical operators. And semantics aside, they can and sometimes should be used as such in C# - for those cases where you want a logical operator without short-circuiting (i.e. one of the operands is a method call with side-effects - which would be a whole nother type of questionable practice, but the language allows it and it has is uses). So in that sense the OP is correct, & and && do the same thing except && short-circuits. Of course, they don't do exactly the same thing, because & can also be used on non-boolean types as a bitwise operator. So (4 & 5) is meaningful, whereas 4 && 5 is not.

Lost User

Absolutely, because && and || wouldn't work with ints (and uints).

James Lonero

The "answer" person's assumptions doesn't seem to match with what you have in your message. Using & is different than using && and the results could be different, depending on what you are comparing. Since both return either true of false, there will not be a difference in the result. (The only difference is how the result is achieved.) In C and C++, you can "AND items that are not boolean as: int i, j; i = 1; j = 2; if (i and j) --> result is false (bitwise AND: 1 & 2 yields 0 or false). if (i and j) --> result is true (logical AND: 1 && 2 yields non-zero or true). Hope this helps.

Mel Padden

Fabio V Silva wrote:

If you're working as C# developer I think you should RTFM.

You, sir, are a disgrace. Not only are you inaccurate in your assertions, you display the two traits I detest most about *some* people who work in this profession - a lack of respect for those around you, and a blinkered solipsism bordering on egomania. Wise the f**k up son. Nobody's impressed.

Smokie, this is not 'Nam. This is bowling. There are rules. www.geticeberg.com http://melpadden.wordpress.com