VBA Loops + Arrays

[Kengh]

Hey guys, I am a student and am taking a class in VBA modeling. I've had one assignment prior to this one where I had to use a Do loop, but other than that I am not skilled in VBA whatsoever. I was hoping I could post the description of the project and get someone to lead me in the right direction. This assignment requires the use of Arrays, and I do not understand them at all as well as other parts of this project. Thanks in advance for any help.

The finished product should have two boxes, one for the encrypted data and one for the un encrypted, and also two buttons, one to encrypt and the other to un-encrypt.
Suppose we want to encrypt data for security reasons. Assuming the “data” entered is always a 4 digit integer, write a program to encrypt the data as follows: replace each digit by (the sum of that digit plus 7) modulus 10, then swap the first digit with the third and swap the second digit with the fourth. Print the encrypted integer in the box (Hint: to build a sting of integers, use the concatenate symbol &). For this assignment, you must use an array to store the four values, and put it within a loop for extracting the values using the MID function. Next, write a routine to decrypt a number back to its original value.

[pike]

Hi Kengh,
Welcome to the forum.
Please take a few minutes to read the forum rules, and then amend your thread title accordingly

[Kengh]

So far I have come up with:

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[Andrew-R]

I still don't think you're there with your title - try something that describes the problem, "Help understanding arrays", perhaps.

To answer your main question an array is a variable which has multiple elements, referenced by an index number (or numbers, but let's not go there yet).

So, for example, if I wanted to write a VBA program to ask for three numbers I could code this...

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That would work, but if I wanted to get 10 numbers, or 100, or even more it would get very, very long-winded and be hard to work with, so I could define an array, like so...

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Functionally these two programs are identical, but the second one can be expanded to allow for the input of any number of numbers, just by changing the value assigned to HowManyNumbers.

All of the numbers input are stored in the array GetNumber, but each one is stored in a unique element of that array, referenced by number, so if I wanted to output the first number entered I could say

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More importantly I can deal with the numbers one at a time by putting them inside a For...Next loop, so I could output the numbers in the order they were entered with the code...

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Arrays are absolutely essential to efficient coding, because they allow you to deal with sets of values, rather than having to reference each one individually. I don't mean to be rude, but if you're taking a VBA course shouldn't they be teaching you this sort of thing?

[teylyn]

Kengh, that title is in no way better. It does not describe the issue and would be useless in a Google search. Also, make sure to wrap your code in code tags.

You have accepted the forum rules when you joined. Read them!

[Andrew-R]

You need to put your code in code tags, or you'll be in more trouble.

As this is an assignment I think it would be wrong for me to just give you the answer, but I've put a few comments in your code...

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[pike]

hi Kengh
If you are having problems changing the title or adding code tags let me know and I can help

[Kengh]

Changed my thread title and depicted the code properly. I am having trouble understand what loop to make for this and how to make it Mod10 as it says in the project description. basically the encrypted number is supposed to be 4 digits just like the encrypted one, so adding 7 to a number higher than 3 gives you a two digit number and that will not work.

[Kengh]

Gahhh this may be close, but still wrong. Any help is greatly appreciated!

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What do I need to change

[Kengh]

Update: Got it to work thanks to Andrew-r! Thank you to everyone that helped!