# Round up to 100% in .NET

Your help is needed to build a function to recalculate the percentages so that it adds up to 100%.
For example if I have a list of records like:
SalesId Sales(\$) Percentage
1            1252        33.33
2            1248        33.33
3            1250        33.33

List size 3 to 20 items, sales could have any value > 0. The records are stored in a List<SaleDetails> object.
Because of normal rounding the percentage  total does not add up to 100%. Sample above is 99.99%.
SalesId Sales(\$) Percentage
1            1252        33.34
2            1248        33.33
3            1250        33.33
P.S.  Example above shows fix on highest value, but the adjustment(s) could be done to any or all of them.
Disclaimer: Ideally we need to create the "Illusion" that  percentage total adds up to 100%. User request.

Thanks
LVL 36
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Commented:
Pseudo VB code:
``````Dim difference = 100 - SUM(Of Records.Prercents)
IF difference = 0 Then Return
delta = IF(difference>0, 0.01, -0.01)
For i = 0 To Records.Count - 1
Records(i).Persentage+= delta
difference-= delta
IF difference = 0 Then Exit For
Next
``````
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Commented:
Two things:

1)  This isn't really a question so much as it is a request to have someone else do your work for you...
2)  You haven't spelled out what the rules for balancing these percentages. Does the first person get the difference between the sum of everyone and 100%? Is it spread evenly across everyone? What happens if the sum is over 100%? Do you take away in a similar fashion?
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Freelance programmer / ConsultantCommented:
To be picky the percentages in your example do add up to 100% - just what you display does not.
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Software EngineerAuthor Commented:
My question was directed towards someone who has done a similar job as the current requirements are vague (e.g. the question) but what we need is to DISPLAY the correct rounded values.
As business rules, for the people that has not done this before, please use largest remainder method that for our case could be applied as follows:
1. Rounding everything down.
2. Getting the difference in sum and 100
3. Distributing the difference by adding 0.01 to items in decreasing order of their decimal parts. (e.g. xx.338 > xx.336)
Note: If numbers are the same, just add to the percentage number in the first record.

MAS
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Commented:
1. Rounding everything down.
2. Getting the difference in sum and 100
3. Distributing the difference by adding 0.01 to items in decreasing order of their decimal parts.
Exactly what my sample do.
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Freelance programmer / ConsultantCommented:
@MAS
You have actually posted the answer to your own question.  Is there a reason you can't implement it?
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Software EngineerAuthor Commented:
AS I said before I am looking for alternatives, my suggested algorithm is just one way of doing, I am looking more for gotchas that people have found in production when dealing with the same issue.
@Ark: Thanks, but item 2 is the where the real task is because if the first record is 0.10 but the second record is 0.55, the difference should go the second record.
@AndyAinscow: My major challenge is time, I have been dragged to another critical issues this week. This is a piece of code that is client facing thus it requires careful design and coding not just  a hack.
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Commented:
//the difference should go the second record
Dim recordsOrdered=Records.OrderByDescending(function(x) x.Percents)
For i=0.....
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Freelance programmer / ConsultantCommented:
If you require code to be written for you then offer it as a gig that you will pay for the work.

ps.  You've probably spent more time writing in this question than actually implementing your logic as code.
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Software EngineerAuthor Commented:
Thanks, it is close enough to what I have I mind. Again, I was looking more for gotchas that people have found in production when dealing with the same issue, but I found SO question that have this info.
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