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Convert byte array to integer with lower and upper bound [closed]

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I have a method that pseudo-randomly encrypts a byte array. I would like to convert the encrypted byte-array to a C# int (4 bytes), while observing a user-specified lower and upper bound (e.g. give me a number between 1 and 10)
What is the most secure and performant way of achieving this?

You could use System.ByteConverter.ToInt32(arr, start_index).
From your description of the array, the start index would likely be zero.
I am not sure what you mean by upper and lower bound, but if you mean you want a random number, you could use a variety of functions to get a value in between the two numbers. If you have semi-uniform distribution, the modulus function would work nicely. In that case, your random number would simply be lowerBound + (System.ByteConverter.ToInt32(arr, start_index) % (upperBound - lowerBound)).

How to calculate a logical curve along a set of values? [closed]

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I am trying to take a float value, with an arbitrary minimum and maximum possible value, and convert it to a linear scale, for representation on a bar-shaped indicator. The problem is, I can't just lerp it between the minimum and maximum, because the maximum value will always be dramatically higher than the minimum value. I have an array of arbitrary values that I want to act as intermediate points between the minimum and maximum. Now I just need to calculate a logical best-fit curve through the points. Each value is always larger than the last, and the rate of increase in value accelerates the further up you go, but there is no simple formula for calculating this rate of acceleration.
Here's an example of the values that may be used:
6.0, 13.5, 30.0, 75.0, 375.0
where 6 is the minimum, and 375 is the maximum.
If x is exactly one of these values, I would want a simple value depending on how many total values there are, I.E 0, 0.25, 0.5, 0.75, 1. The issue is calculating the in-between values.
How would I go about achieving this? I apologize if a question like this has already been asked, as it feels like a common problem, although I didn't know what to search for. If this has already been answered before, please just point me in the right direction.

Reposting my comment as an answer, as requested.
If a curve might be y(x) = k^(ax+b), take logs of both sides and you have a linear relation. As pointed out tho, this is maths not programming.
I’d pick k = 2, e or 10 for easier implementation; a & b you work out from data.

C# Check if a string is a Sentence [closed]

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Basically I want to check if a String is a Sentence ("Hello, I am Me!") or Symbol Spam ("HH,,,{''{"), without using the number of symbols as a factor as much as possible. Right now it just detects based on a counter of symbols, but when someone says something with lots of punctuation, they get kicked.
Help?

If the number of symbols in the text is not sufficient, and you don't want to use something too fancy (or bought) could I suggest implementing one or more of these further steps (of increasing difficulty):
Make a count of all A-Za-z and space characters in the string and make a ratio of this to the count of symbols - so if they write a sentence then !!!!!!!!!!!!! at the end it still doesn't snag as the ratio is high enough.
If this still isn't discerning enough, add a further check if you pass item 1...
Count numbers of consecutive A-Za-z characters in the string - work out the average length of these 'words' - if the average is too short then it is probably spam.
These can be done in RegEx reasonably easily - If you want more sophistication then you have to use something written by someone else that has much more developed statistical methods (or start reading lexographical university papers that are beyond me!)

How to Program 'Chance'? [closed]

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i have an idea of something but i don't have a clue how to do it :D
basically just like in the games for example, every 6 hours you can open a chest where you can grab some item for free. Now i want to have a chest that the user can open every 6 hours, i have the items written in mysql server where every item gives experience points to the user. but how to do it?
lets say the database have 15 items, now every item have its chance value for example
nothing = 75% of getting it
sword_1 = 15% of getting it
sword_2 = 30% of getting it
any idea how to do it?

Define a range of % to get an item
Example - sword_1 = 0-15%, sword_2 = 15-45%
Note that the numbers above don't add up to 100%, so unless you really want return more than one time, sometimes.. the above ranges takes care of getting nothing.
If you want multiple rewards on a roll, simply adjust the ranges accordingly.
Generate a random number between 0 and 100. For the items where generated number falls within the range, those are your rewards won for that round.

You could assign a numeric value to each of your items in the table, the percentage of getting it would be the difference between it and its next lowest number.
Nothing, 60 (60% chance)
sword_1, 70 (10% chance)
sword_2, 100 (30% chance)
Make sure that your max item is 100.
You can then do a select from that table with a random number:
SELECT * FROM ChestItems WHERE ChanceValue < FLOOR(RAND() * 100) ORDER BY ChanceValue DESC LIMIT 1;
There are several (and much better) ways you can do this. This is just a quick example.

Incrementing across a changeable distance 0-1 keeping time equal [closed]

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I'm unable to think through this one I think it's one of those moments where the answer is really simple but I'm too close to the problem to see the solution.
I have a distance that's changeable and an object that has to traverse this distance in the same time regardless of length.
The start of the distance is valued as 0 and the end of the distance is valued as 1.
Obviously the incrementation will be smaller the larger the length to keep the times equal.
What formula could I use to calculate the 0-1 incrementation but keep the time taken equal.
I know it seems overly complicated way to increment but it's part of the third party plugin I've been given.
I'm coding in C#.
Thanks.
[EDIT]
Sorry I wasn't very clear.
For incrementation the start point is always 0 and the end point is always 1.
So the object can move += 0.5 for example.
so when the length increase from say 30 to 65 it should take longer to increment from 0 to 1.

So you are looking for a way to have a number x in the range [0,1] that maps to some y in some arbitrary range [min,max], and are looking for the increment value a such that if x -> y then x + a -> y + b for some constant b? If I have understood your question correctly, then your a value should be:
a = b / (max - min) note: make sure to format this correctly for C#, especially be sure to cast and that sort of thing.
This is basically saying that a should be the fraction of the range that a spans, that if b is half the range from min to max, then a should be 0.5, and if b spans one fifth the range, a should be 0.2.