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Thread Rules
1. This is not a "do my homework for me" thread. If you have specific questions, ask, but don't post an assignment or homework problem and expect an exact solution.
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On March 27 2012 10:57 berated- wrote:Show nested quote +On March 27 2012 10:27 teamamerica wrote:Hey guys, I'm a pretty noob cs guy (2nd year of B.S) but I was wondering what you guys thought of this list of what every cs major should know. It pretty comprehensive and something I'd like to refer to from time to time as a kind of checkoff list of things to learn. If you know all of those things I doubt there is a company in the world that wouldn't hire you. We ask the people we are trying to hire to have about 1/4 of those requirements and still can't find them.
Pretty interesting. I read the K & R book and luckily I know and have experience with everything there except hash lookups, which I'll be writing this summer for use in projects next term. I'm also solid on the mathematics (take a ton at my college). Also taking multiple years of C++ and doing many large projects from scratch in C++. Have experience writing in Assembly as well, but not a whole lot. Would love to learn more but have to wait until 3rd year where we program an 8-bit microprocessor to run a game on a hand-held device. Going to be so fun! Hopefully I can apply what I learn on a side-project of creating a SNES game. Always been interesting in coding something for the SNES. Also have classes on operating systems and will be creating networking for game projects in C++. Many classes on graphics programming, AI, databases and data structures, there's a machine learning class though it's not on the required course sequence.
Looks like I'm in a good position 
https://www.digipen.edu/academics/degree-programs/real-time-interactive-simulation/course-sequence/
https://www.digipen.edu/academics/course-catalog/course-descriptions/computer-science-cs/
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Hey guys, for my university assignment , i have to create two random rectangles and im having trouble trying to code it, is anyone familiar with this?
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Spacefighting, your description of the assignment is to vague to be of no use to help you, really. (What langauge? What libraries? What sort of result do you need?)
To create a random rectangle, you need 4 random points, or 8 random numbers (x and y) to be the 4 corners. So generate 8 random numbers, call them the corners of the rectangle, and you're done.
Unless you need to draw them? Or they have to be within a certain size/area? That would complicate things slightly.
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On March 28 2012 01:00 ThatGuy wrote:
Yeah the solution I currently came up with is O(n/2 * n^2), but I usually don't deal with stuff that goes beyond O(n^2), so I wasn't sure if I was being stupid. Thanks for the reply. On the plus side, once it's constructed I don't really have to deal with it again lol.
EDIT: Actually it looks a bit less than that, since it keep looping through a smaller list on every iteration...w/e.
Unless you need a really precise efficiency, O((n/2)*(n^2)) is on the order of O(n^3).
Unless you're doing this for an upper-level Master's Degree class, or an independent research project in algorithms, O(n^3) is good enough.
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On March 28 2012 05:32 gauauu wrote:
Spacefighting, your description of the assignment is to vague to be of no use to help you, really. (What langauge? What libraries? What sort of result do you need?)
To create a random rectangle, you need 4 random points, or 8 random numbers (x and y) to be the 4 corners. So generate 8 random numbers, call them the corners of the rectangle, and you're done.
Unless you need to draw them? Or they have to be within a certain size/area? That would complicate things slightly.
Ops sorry, the language used is java and its about rectangle class, im a first year comp sci major and i am uncertain of how to create a random rectangle with this.
The reault im looking for is to create 2 random rectangles, choose a random point within them and see whether they intersect at that given point.
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On March 28 2012 07:14 SpaceFighting wrote:Show nested quote +On March 28 2012 05:32 gauauu wrote:
Spacefighting, your description of the assignment is to vague to be of no use to help you, really. (What langauge? What libraries? What sort of result do you need?)
To create a random rectangle, you need 4 random points, or 8 random numbers (x and y) to be the 4 corners. So generate 8 random numbers, call them the corners of the rectangle, and you're done.
Unless you need to draw them? Or they have to be within a certain size/area? That would complicate things slightly. Ops sorry, the language used is java and its about rectangle class, im a first year comp sci major and i am uncertain of how to create a random rectangle with this. The reault im looking for is to create 2 random rectangles, choose a random point within them and see whether they intersect at that given point.
The Java API is your best friend: API for Rectangle().
To get random numbers in Java, check out: http://docs.oracle.com/javase/1.4.2/docs/api/java/lang/Math.html. Look for the Math.random() method.
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On March 28 2012 07:52 Millitron wrote:Show nested quote +On March 28 2012 07:14 SpaceFighting wrote:On March 28 2012 05:32 gauauu wrote:
Spacefighting, your description of the assignment is to vague to be of no use to help you, really. (What langauge? What libraries? What sort of result do you need?)
To create a random rectangle, you need 4 random points, or 8 random numbers (x and y) to be the 4 corners. So generate 8 random numbers, call them the corners of the rectangle, and you're done.
Unless you need to draw them? Or they have to be within a certain size/area? That would complicate things slightly. Ops sorry, the language used is java and its about rectangle class, im a first year comp sci major and i am uncertain of how to create a random rectangle with this. The reault im looking for is to create 2 random rectangles, choose a random point within them and see whether they intersect at that given point. The Java API is your best friend: API for Rectangle(). To get random numbers in Java, check out: http://docs.oracle.com/javase/1.4.2/docs/api/java/lang/Math.html. Look for the Math.random() method.
Oh kewl thanks, exactly what im looking for, programming seems to be difficult for me, gotta study hard!
Thanks once again
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On March 28 2012 05:29 SpaceFighting wrote:
Hey guys, for my university assignment , i have to create two random rectangles and im having trouble trying to code it, is anyone familiar with this?
Really really depends on the language for how you actually go about it but the concept is pretty simple.
1. Find the random number generator for your language
2. Get random values within the range you have (0 - screen width and 0 - screen height I'd imagine):
- start x coord
- start y coord
- height of rect
- width of rect
3. repeat for second rectagle.
From my experience most languages will ask you for an (x.y) for top left corner and then a height and width so your're looking at something like:
Rectangle rect = new Rectangle(x,y,length,width); << Very java esk
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On March 28 2012 09:39 dogmeatstew wrote:Show nested quote +On March 28 2012 05:29 SpaceFighting wrote:
Hey guys, for my university assignment , i have to create two random rectangles and im having trouble trying to code it, is anyone familiar with this? Really really depends on the language for how you actually go about it but the concept is pretty simple. 1. Find the random number generator for your language 2. Get random values within the range you have (0 - screen width and 0 - screen height I'd imagine): - start x coord - start y coord - height of rect - width of rect 3. repeat for second rectagle. From my experience most languages will ask you for an (x.y) for top left corner and then a height and width so your're looking at something like: Rectangle rect = new Rectangle(x,y,length,width); << Very java esk
Just keep in mind that this can place the rectangle (parts of it at least) outside of the screen if for example start x coord + rectangle width > screen width.
Do it like this:
- randomise height + width of rectangle (max limit < screen size)
- randomise start x coordinate (max limit < (screen width - rectangle width))
- randomise start y coordinate (max limit < (screen height - rectangle height))
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I was looking for an example how to use 2 threads, so I found this one:
http://www.cs.nccu.edu.tw/~linw/javadoc/tutorial/java/threads/simple.html
However, both threads execute the same code. How can one make each thread do something else? E.g. this thread will clean floor, while the other will wash clothes. At first I thought about variable check, but if threads are 4... is it still possible?
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For everything that you want to execute in such a thread, simply create an instance of the Runnable interface. Then you just call new Thread(runnable).start(); (where runnable is your Runnable instance) for every thread you want to start besides the main thread and it will execute the runnable's run(){..} method in a separate thread.
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Can anyone explain how Wolfram Alpha does their computations so quickly? It's kinda ridiculous imho. I haven't looked into it much. Just wondered this earlier today in class.
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On April 03 2012 11:19 Blisse wrote:
Can anyone explain how Wolfram Alpha does their computations so quickly? It's kinda ridiculous imho. I haven't looked into it much. Just wondered this earlier today in class.
Brute-force computation is what computers were invented for. Its amazing how quickly they can plow through arithmetic expressions. You don't even need exceptionally efficient algorithms for most pure arithmetic calculations. Basically, if it can be represented by an equation and doesn't involve summations, almost any modern computer can do it pretty much instantly. What slows them down are repeated calculations. For instance, in a videogame, when your computer tries to draw something on the screen, it does so by drawing many triangles. It can draw a single triangle in a fraction of a millisecond, but if you have to draw 20,000 of them, those fractions of a millisecond add up.
I would suspect WA does have exceptionally efficient algorithms as well, but they would be just as fast without them for most users needs. Only the people running N-body orbital integrators, and other insane stuff need the high-efficiency algorithms.
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Hey, I was doing homework that ended up like this: http://pastebin.com/VujQAxPq (~50 lines long)
While it produced a valid answer, it used an unreasonable amount of memory to do it (7.5GB of 8 RAM that was free + tons of pagefile on top of that).
Anyone know what's happened to make it so memory consuming?
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On April 04 2012 10:58 Mittens wrote:Hey, I was doing homework that ended up like this: http://pastebin.com/VujQAxPq (~50 lines long) While it produced a valid answer, it used an unreasonable amount of memory to do it (7.5GB of 8 RAM that was free + tons of pagefile on top of that). Anyone know what's happened to make it so memory consuming?
Im Not sure if i understand your question correct...
You wonder why your program uses ~500mb Memory ?
If so, You have two Byte arrays with total of 15 Byte * 39506988 loop = ~ 59260482 Byte
= 565 mb
I hope i got that right :/
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I use Java nested class, but it doesn't work on Linux although I get a file similar to: mainclass$innerclass.class (the problem is the inner class isn't executed)
There is no problem on Windows though. Any suggestions?
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On April 04 2012 10:58 Mittens wrote:Hey, I was doing homework that ended up like this: http://pastebin.com/VujQAxPq (~50 lines long) While it produced a valid answer, it used an unreasonable amount of memory to do it (7.5GB of 8 RAM that was free + tons of pagefile on top of that). Anyone know what's happened to make it so memory consuming?
byte[] hashedBYTES = hashSha.ComputeHash(byteContainer);
this line could eat up memory, have you tried to declare hashedBYTES outside of the loop? that should be better for performance anyway.
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On April 04 2012 22:56 darkness wrote:
I use Java nested class, but it doesn't work on Linux although I get a file similar to: mainclass$innerclass.class (the problem is the inner class isn't executed)
There is no problem on Windows though. Any suggestions?
Read up on how your Linux JVM handles inner classes. I suspect its a linking issue though.
Anyways, I got a question TL. I'm working on a fairly large project in Java, and I'm using Eclipse. My problem is that each version only changes a couple of methods in each class, so I like to collapse the ones that I'm not working on. But, since each version gets its own project, Eclipse seems to forget what methods I've collapsed, and displays them all, and its getting annoying to have to manually collapse them all every time I start a new version. Is there any way to make it remember this kind of thing between projects?
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On April 05 2012 02:27 Millitron wrote:
Read up on how your Linux JVM handles inner classes. I suspect its a linking issue though.
Any links? I can't find anything useful in particular.
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On April 05 2012 05:28 darkness wrote:Show nested quote +On April 05 2012 02:27 Millitron wrote:
Read up on how your Linux JVM handles inner classes. I suspect its a linking issue though.
Any links? I can't find anything useful in particular.
Actually, no. This is harder to look up than I imagined it would be. I can't find much about how any Linux JVM's work at all, let alone how they deal with this admittedly unique situation.
What I mean by a linking issue though, is that the classes aren't being linked together properly. In C++, you do this with DLL's or .lib files, but in Java, the JVM takes care of it for you normally.
Does your program outright crash, or just not execute the inner class stuff?
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EPT
