Morton codes get errors when running

After 24 hours, I will venture a couple of observations.

Revealing my ignorance, but my first observation is that this does not look like VBA. If this code is supposed to be functional without modification, then my first question is "what programming language is this?" From there, running the code should be as "simple" as obtaining a compiler for that programming language, compiling the code, and running it.

If I were starting from scratch doing something like this (in an Excel environment) I would probably:

1) Use Excel's DEC2BIN() function to convert the decimal numbers to binary.
2) Use Excel's MID() of VBA's Mid() function to extract individual characters from the binary numbers.
3) Concatenate the result in the desired order.

There are some details to figure out there, but I am not sure if that is how you want to approach the problem or not. In some of my research, I found some concepts that are over my head ("bitwise processing" for example), and you may be looking for that kind of implementation.

I guess at this point I would ask for further clarification. Exactly what do you need help with? Are you required to use the code that you posted and you need help identifying the programming language and obtaining a compiler? Are you trying to translate this code as close as possible into VBA and/or Excel functions? Is this just sample code, and you will accept any approach that successfully encodes/decodes Morton code?

I copied the code you give an pasted it into a module in your spreadsheet. I then entered =Morton(A1,A2,A3) into A7, and the function returned 1095, which, if I understand correctly, is the value you think it should return. This is different from the spreadsheet version where S5 calculates 1096.

So, I modified your code with a simple Stop statement at the beginning:

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With the Stop statement in place, I executed the function (select A7, press F2 and enter) and enter debug mode. Then, while stepping through the function, I compared what the function was doing with the spreadsheet version. (If you are unfamiliar with VBA's debugging tools: http://www.cpearson.com/excel/DebuggingVBA.aspx ). The difference between the UDF and the spreadsheet version seems to be in column K. When the UDF got to the same point as K3, it added S2 and J3. The spreadsheet version added S2 and J2. It appears to me that K3 should be =S2+J3 (and copied down) instead.

Can you supply an example with the incorrect results as well as the expected correct results? I changed the 4 to 8, tested on x=18, y=59, z=5 and the function gave me 79134. Expanding your spreadsheet breakdown and I also get 79134. If 79134 is the correct answer for this particular problem, it should be as easy as changing the For i=... statement. If 79134 is not the correct result, then we need to know what the correct result should be, and, perhaps, some of the intermediate values along the way in order to debug.