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  • When setting a form's opacity should I use a decimal or double?

    - by Eggs McLaren
    I'm new to C#, and I want to use a track-bar to change a form's opacity. This is my code: decimal trans = trackBar1.Value / 5000 this.Opacity = trans When I try to build it, I get this error: Cannot implicitly convert type 'decimal' to 'double' I tried making trans a double, but then the control doesn't work. This code worked fine for me in VB.NET. What do I need to do differently?

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  • Newbie programmer looking for a fun, small project (pref. C++/Python)

    - by Francisco P.
    Hello everyone, I have some experience in Scheme and C++ (read: a semester of each) I know the very basics of Python (used it for physics simulations with the Visual Python module). Can you recommend me some fun and small (i.e. don't take much time) projects on either Python or C++? I have no real preferences, just that it is fun :P Thanks for your time! PS: I've tried projecteuler and python challenge. Euler is good, but more about math than coding, and py challenge just didn't work for me.

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  • Unexpected behaviour of Order by clause

    - by Newbie
    I have a table which looks like Col1 col2 col3 col4 col5 1 5 1 4 6 1 4 0 3 7 0 1 5 6 3 1 8 2 1 5 4 3 2 1 4 The script is declare @t table(col1 int, col2 int, col3 int,col4 int,col5 int) insert into @t select 1,5,1,4,6 union all select 1,4,0,3,7 union all select 0,1,5,6,3 union all select 1,8,2,1,5 union all select 4,3,2,1,4 If I do a sorting (ascending), the output is Col1 col2 col3 col4 col5 0 1 5 6 3 1 4 0 3 7 1 5 1 4 6 1 8 2 1 5 4 3 2 1 4 The query is Select * from @t order by col1,col2,col3,col4,col5 But as can be seen that the sorting output is wrong (col2 to col5). I want the output to be every column being sorted in ascending order i.e. Col1 col2 col3 col4 col5 0 1 0 1 3 1 3 1 1 4 1 4 2 3 5 1 5 2 4 6 4 8 5 6 7 Why so and how to overcome this? Thanks in advance

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  • What is a really simple explanation of unit testing?

    - by ensnare
    I've never done any unit testing before, and would like to learn what it is and how it can be useful in my Python code. I've read through a few Python unit testing tutorials online but they're all so complicated and assume an extended programming background. I'm using Python with Pylons to create a simple web app. Any simple examples would be greatly appreciated. Thanks!

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  • Why won't the following haskell code compile?

    - by voxcogitatio
    I'm in the process of writing a small lisp interpreter in haskell. In the process i defined this datatype, to get a less typed number; data Number = _Int Integer | _Rational Rational | _Float Double deriving(Eq,Show) Compiling this fails with the following error: ERROR "types.hs":16 - Syntax error in data type declaration (unexpected `|') Line 16 is the line w. the first '|' in the code above.

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  • As a PHP developer thinking of making Perl a secondary strong suit, what do I need to know?

    - by Hexagon Theory
    I consider myself quite fluent in PHP and am rather familiar with nearly all of the important aspects and uses, as well as its pratfalls. This in mind, I think the major problem in taking on Perl is going to be with the syntax. Aside from this (a minor hindrance, really, as I'm rather sold on the fact that Perl's is far more readable), what are some key differences you think I should make myself aware of prior to taking on the language?

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  • vector related memory allocation question

    - by memC
    hi all, I am encountering the following bug. I have a class Foo . Instances of this class are stored in a std::vector vec of class B. in class Foo, I am creating an instance of class A by allocating memory using new and deleting that object in ~Foo(). the code compiles, but I get a crash at the runtime. If I disable delete my_a from desstructor of class Foo. The code runs fine (but there is going to be a memory leak). Could someone please explain what is going wrong here and suggest a fix? thank you! class A{ public: A(int val); ~A(){}; int val_a; }; A::A(int val){ val_a = val; }; class Foo { public: Foo(); ~Foo(); void createA(); A* my_a; }; Foo::Foo(){ createA(); }; void Foo::createA(){ my_a = new A(20); }; Foo::~Foo(){ delete my_a; }; class B { public: vector<Foo> vec; void createFoo(); B(){}; ~B(){}; }; void B::createFoo(){ vec.push_back(Foo()); }; int main(){ B b; int i =0; for (i = 0; i < 5; i ++){ std::cout<<"\n creating Foo"; b.createFoo(); std::cout<<"\n Foo created"; } std::cout<<"\nDone with Foo creation"; std::cout << "\nPress RETURN to continue..."; std::cin.get(); return 0; }

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  • Regex, replace path to resource, modify resource name

    - by jerome
    Hi all, I'd like to use a JS regex to take a string such as the following: 'http://www.somedomain.com/some_directory/some_other_directory/some_image.jpg' And turn it into this: 'http://www.some_other_domain.com/another_directory/yet_another_directory/size1_some_image.jpg' Any hints? Additionally, any pointers for books or other resources that give a gentle introduction to mastering regexes in JS and other languages?

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  • Does everything after my try statement have to be encompassed in that try statement to access variab

    - by Mithrax
    I'm learning java and one thing I've found that I don't like, is generally when I have code like this: import java.util.*; import java.io.*; public class GraphProblem { public static void main(String[] args) { if (args.length < 2) { System.out.println("Error: Please specify a graph file!"); return; } FileReader in = new FileReader(args[1]); Scanner input = new Scanner(in); int size = input.nextInt(); WeightedGraph graph = new WeightedGraph(size); for(int i = 0; i < size; i++) { graph.setLabel(i,Character.toString((char)('A' + i))); } for(int i = 0; i < size; i++) { for(int j = 0; j < size; j++) { graph.addEdge(i, j, input.nextInt()); } } // .. lots more code } } I have an uncaught exception around my FileReader. So, I have to wrap it in a try-catch to catch that specific exception. My question is does that try { } have to encompass everything after that in my method that wants to use either my FileReader (in) or my Scanner (input)? If I don't wrap the whole remainder of the program in that try statement, then anything outside of it can't access the in/input because it may of not been initialized or has been initialized outside of its scope. So I can't isolate the try-catch to just say the portion that intializes the FileReader and close the try statement immediately after that. So, is it the "best practice" to have the try statement wrapping all portions of the code that are going to access variables initialized in it? Thanks!

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  • Question about Radio button/PHP/MySQL

    - by Marcelo
    Hi, I'm an engineering student and I'm developing a simple software based on HTML, PHP and mysql. I learned this topics on w3schools. I know only the basics. I tried to search about this in this website but I found questions about PHP, MySQL and HTML radio buttons which were much more complex than I need and that I could understand. Sorry for the English. (Q1) Ex: $email=$_REQUEST['email'] , in this case the input is text, if it where like a radio button for ex: sex: male or female, how would it be? (Q2) what would be the type of this field (for exemple sex in question 1) in the database: text, int, varchar ? Thanks for the attention

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  • I'm having a problem identifying a floating point exception.

    - by Peter Stewart
    I'm using c++ in visual studio express to generate random expression trees for use in a genetic algorithm type of program. Because they are random, the trees often generate (I'll call them exceptions, I'm not sure what they are) Thanks to a suggestion by George, I turned the mask _MCW_EM on so that hardware interrupts are turned off. (the default) So, the program runs uninterrupted, but some of the values returned are: -1.#INF, -1.#NAN, -1.#INV. I don't know how to identify these so that I can throw an exeption: if ( variable == -1.#INF) ?? DigitalRoss in this post seemed to have the solution, but as I understood it I couldn't make it work. I've been looking all over the place for this simple bit of code, that I assumed would be used all the time, but have had no luck. thanks

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  • Get absolute (base) url in sinatra.

    - by berkes
    Right now, I do a get '/' do set :base_url, "#{request.env['rack.url_scheme']}://#{request.env['HTTP_HOST']}" # ... haml :index end to be able to use options.base_url in the HAML index.haml. But I am sure there is a far better, DRY, way of doing this. Yet I cannot see, nor find it. (I am new to Sinatra :)) Somehow, outside of get, I don't have request.env available, or so it seems. So putting it in an include did not work. How do you get your base url?

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  • How do I initialize a fixed byte array?

    - by Jurily
    I have the following struct: [StructLayout(LayoutKind.Sequential, Pack = 1)] struct cAuthLogonChallenge { byte cmd; byte error; fixed byte name[4]; public cAuthLogonChallenge() { cmd = 0x04; error = 0x00; name = ??? } } name is supposed to be a null-terminated ASCII string, and Visual Studio is rejecting all my ideas to interact with it. How do I set it?

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  • run multiple programs in linux

    - by Betamoo
    I am trying to write a .sh file that runs many programs simultaneously I tried this prog1 prog2 But that runs prog1 then waits until prog1 ends and then starts prog2... So how can I run them in parallel? Thanks

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  • jQuery click event not working when mouse moves from one div to another with button held down

    - by Acorn
    I've made a page that uses jQuery to allow you to place <div>s on the page based on your mouse coordinates when you click. The page And here's the javascript: $('document').ready(function() { $("#canvas").click(function(e){ var x = e.pageX - this.offsetLeft; var y = e.pageY - this.offsetTop; $(document.createElement('div')).css({'left':x + 'px', 'top':y + 'px'}).addClass('tile').appendTo('#canvas'); }); }); I've found that if you mousedown in the div#canvas and mouseup with your pointer over a placed <div> (or vice versa) then a new <div> doesn't get placed. Why is this?

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  • can I have multiline text with GD and PHP?

    - by alekone
    hello! I'm trying to output multiline text with GD+PHP but can't get it working. my php knowledge is really basic. here's the code, any idea on how to output 2 or 3 lines of text? $theText = (isset($_GET['caption']))? stripslashes($_GET['caption']) :''; imagettftext($baseImage, $textSize, $textAngle, $textXposition, $textYposition, $textColor, $fontName, $theText);

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  • how to start learning Java scripting

    - by antriksh
    Dear All, I am experienced in the technical support like Linux, oracle, sunos etc and but if i say scripting i know little bit of bash. Now i promoted to manage technical engineers inuding some java script developers, so i want to learn java scripting so that i can understand engineers. Hope you understand. Can you please advise me how can i start java scripting and point me to some simple docs and examples.

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  • Java method: retrieve the inheriting type

    - by DrDro
    I have several classes that extend C and I would need a method that accepts any argument of type C. But in this method I would like to know if I'm dealing with A or B. * public A extends C public B extends C public void goForIt(C c)() If I cast how can I retrieve the type in a clean way (I just read using getClass or instanceof is often not the best way). *Sorry but I can't type closing braces

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  • convert string to dict using list comprehension in python

    - by Pavel
    I have came across this problem a few times and can't seem to figure out a simple solution. Say I have a string string = "a=0 b=1 c=3" I want to convert that into a dictionary with a, b and c being the key and 0, 1, and 3 being their respective values (converted to int). Obviously I can do this: list = string.split() dic = {} for entry in list: key, val = entry.split('=') dic[key] = int(val) But I don't really like that for loop, It seems so simple that you should be able to convert it to some sort of list comprehension expression. And that works for slightly simpler cases where the val can be a string. dic = dict([entry.split('=') for entry in list]) However, I need to convert val to an int on the fly and doing something like this is syntactically incorrect. dic = dict([[entry[0], int(entry[1])] for entry.split('=') in list]) So my question is: is there a way to eliminate the for loop using list comprehension? If not, is there some built in python method that will do that for me?

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