Divide and multiply

[ihsaan]

What is the correct method of dividing and then multiplying in a statement? The following is what I've used but doesn't work.

SheetsRequired = Pages / 4 * 2

[ihsaan]

Ok the following worked

SheetsRequired = (Pages / 4) * 2

[jpbro]

That is the correct method. Are you sure you are using the forward slash in your actual code? If you are using the backslash instead (integer divide), then you will get a different result (because the multiplication will take place before the integer division).

If you are using the exact statement as written above, maybe you could clarify what "doesn't work" means? What value is in Pages, and what result are you getting in SheetsRequired vs. what you are expecting?

Lastly, what are the variable types of Pages and SheetsRequired?

[SamOscarBrown]

A good source that may help you: https://msdn.microsoft.com/en-us/library/fw84t893.aspx

[dilettante]

Sadly MSDN Online seems to have removed the correct VB6 article on operator precedence.

But instead of relying on the VFred link given above you should look up the topic in your MSDN Library CDs you should have installed locally. Ideally you have the October 2001 release installed, but even something a little earlier would be good.

The information will be more accurate and far less misleading.

[jpbro]

Maybe my coffee hasn't kicked in yet, but I can't think of a situation where X/4*2 would not equal (X/4)*2. Can anyone clue me in?

[DataMiser]

There should be no difference in the result from post 1 and post 2 All division and multiplication are preformed in the order it appears from left to right so x/y*z is the same as (x/y)*z

Of course given your code in the OP there is no need for both. x/4*2 = x/2

so

SheetsRequired = Pages / 2

Would yield the same result

[SamOscarBrown]

Sadly MSDN Online seems to have removed the correct VB6 article on operator precedence.

Well, maybe the "VFred" link is not completely understandable (as it doesn't fully 'explain' the precedence order of the combinations shown), but it makes sense to me. But, I suppose the best advice IS to use the resource you suggested.

Anyway,from that link-Order of Precedence:

Attachment 125739

[LaVolpe]

Yepper, that integer division one has bitten me in the past...

(6 / 2 * 3) <> (6 \ 2 * 3)

[dilettante]

There is also the range issue, which is why Kernel32 exports the MulDiv() entrypoint.

[Bonnie West]

Sadly MSDN Online seems to have removed the correct VB6 article on operator precedence.

The VBA version (which is exactly the same as the VB6 version) of the Operator Precedence article is still available though.

Of course given your code in the OP there is no need for both. x/4*2 = x/2

so

SheetsRequired = Pages / 2

Would yield the same result

Another equivalent expression is:

SheetsRequired = Pages * 0.5

Supposedly, multiplication is a lot faster than division, but I don't know if that's still true with the latest CPUs.

There is also the range issue, ...

That doesn't appear to be a problem since integral operands will be first converted to Double before being divided.