5ED4-07A4
doing this normally i just get 5730, im wondering if there is a special way to do this with unsigned numbers? i know that means they cant be negative but not sure how to implement that.
Right, if you are doing that by hand, the best way to do substractions, as far a I know, is the primary school way (of course in hex):
000
5ED4
-07A4
----
5730
Related
Im new so if this question was already Asked (i didnt find it scrolling through the list of results though) please send me the link.
I got a math quiz and im to lazy to go through all the possibilities so i thought i can find a program instead. I know a bit about programming but not much.
Is it possible (and in what programming language, and how) to read only one digit, e.g at the 3rd Position, in a integer?
And how is an integer actually saved, in a kind of array?
Thanks!
You can get rid of any lower valued digit (the ones and tens if you only want the hundreds) by dividing with rounding/truncation. 1234/100 is 12 in most languages if you are doing integer division.
You can get rid of any higher valued digits by using taking the modulus. 12 % 10 is 2 in many languages; just find out how the modulus is done in yours. I use "modulus" meaning "divide and keep the rest only", i.e. it is the opposite of "divide with rounding"; that which is lost by rounding is the final result of the modulus.
The alternative is however to actually NOT see the input as a number and treat it as text. That way it is often easier to ignore the last 2 characters and all leading characters.
I'm currently working a project where I use MARIE Assembly Language to create a version of Hamming code. My initial work has been to first have the user input the 8 bits for the data bits, and to then have the program output the correct 12-bit code word.
In order to find the correct values for the parity bits, I thought that the easiest way might be to load each data bit, which corresponds to a certain parity bit, and to count the number of 1s. However, I have yet to have found a way to have Marie count bits. I know there is no direct instruction to make Marie count bits, but does anyone have any advice on which instruction(s) might lead me towards an answer? I apologize in advance if clarity is lacking, and if it is please let me know so I can edit my question accordingly.
is there any tool or method to figure out what is this hash/cipher function?
i have only a 500 item list of input and output plus i know all of the inputs are numeric, and output is always 2 Byte long hexadecimal representation.
here's some samples:
794352:6657
983447:efbf
479537:0796
793670:dee4
1063060:623c
1063059:bc1b
1063058:b8bc
1063057:b534
1063056:b0cc
1063055:181f
1063054:9f95
1063053:f73c
1063052:a365
1063051:1738
1063050:7489
i looked around and couldn't find any hash this short, is this a hash folded on itself? (with xor maybe?) or maybe a simple trivial cipher?
is there any tool or method for finding the output of other numbers?
(i want to figure this out; my next option would be training a Neural Network or Regression, so i thought i ask before taking any drastic action )
Edit: The Numbers are directory names, and for accessing them, the Hex parts are required.
Actually, Wikipedia's page on hashes lists three CRCs and three checksum methods that it could be. It could also be only half the output from some more complex hashing mechanism. Cross your fingers and hope that it's of the former. Hashes are specifically meant to be difficult (if not impossible) to reverse engineer.
What it's being used for should be a very strong hint about whether or not it's more likely to be a checksum/CRC or a hash.
Okay, so I am trying to drive a 7 segment based display in order to display temperature in degrees celcius. So, I have two displays, plus one extra LED to indicate positive and negative numbers.
My problem lies in the software. I have to find some way of driving these displays, which means converting a given integer into the relevant voltages on the pins, which means that for each of the two displays I need to know the number of tens and number of 1s in the integer.
So far, what I have come up with will not be very nice for an arduino as it relies on division.
tens = numberToDisplay / 10;
ones = numberToDisplay % 10;
I have admittedly not tested this yet, but I think I can assume that for a microcontroller with limited division capabilities this is not an optimal solution.
I have wracked my brain and looked around for a solution using addition/subtraction/bitwise but I cannot think of one at all. This division is the only one I can see.
For this application it's fine. You don't need to get bothered with performance in a simple thermometer.
If however you do need something quicker than division and modulo, then bitwise operations come to help. Basically you would use bitwise & operator, to compare your value to display with patterns describing digits to be displayed on the display.
See the project here for example: http://fritzing.org/projects/2-digit-7-segment-0-99-counting-with-arduino/
You might also try using a 7-seg display driver chip to simplify your output and save pins. The MC14511BCP (a "4511") is a good one. It'll translate binary coded decimal (BCD) to the appropriate 7-seg configuration. Spec sheets are available here and they can be commonly found at electronics parts stores online.
I'm trying to write a program that will help someone study for the GRE math. As many of you may know, fractions are a big part of the test, and calculators aren't allowed. Basically what I want to do is generate four random numbers (say, 1-50) and either +-/* them and then accept an answer in fraction format. The random number thing is easy. The problem is, how can I 1) accept a fractional answer and 2) ensure that the answer is reduced all the way?
I am writing in ASP.NET (or jQuery, if that will suffice). I was pretty much wondering if there's some library or something that handles this kind of thing...
Thanks!
have a look at
http://www.geekpedia.com/code73_Get-the-greatest-common-divisor.html
http://javascript.internet.com/math-related/gcd-lcm-calculator.html
Since fractions are essentially divisions you can check to see if the answer is partially correct by performing the division on the fraction entries that you're given.
[pseudocode]
if (answer.contains("/"))
int a = answer.substring(1,answer.instanceof("/"))
int b = answer.substring(answer.instanceof("/"))
if (a/b == expectedAnswer)
if (gcd(a,b) == 1)
GOOD!
else
Not sufficiently reduced
else
WRONG!
To find out whether it's reduced all the way, create a GCD function which should evaluate to the value of the denominator that the user supplied as an answer.
Learn Python and try fractions module.