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  • Member variable in C++ class that is always constant for all objects of that class?

    - by user1799323
    I'm constructing a class where I have three member variables that I want to always be the same value NO MATTER WHAT. I have class foo{ public: double var_1, var_2, var_3; double x=1, y=2, z=3; [functions go here] }; that gave me an error since I can't initialize a variable like that. But I want x, y and z to always be 1, 2 and 3 respectively. I tried defining them outside the class but that doesn't work since I want them to be member variables of the class. How do I do this?

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  • Does a c/c++ compiler optimize constant divisions by power-of-two value into shifts?

    - by porgarmingduod
    Question says it all. Does anyone know if the following... size_t div(size_t value) { const size_t x = 64; return value / x; } ...is optimized into? size_t div(size_t value) { return value >> 6; } Do compilers do this? (My interest lies in GCC). Are there situations where it does and others where it doesn't? I would really like to know, because every time I write a division that could be optimized like this I spend some mental energy wondering about whether precious nothings of a second is wasted doing a division where a shift would suffice.

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  • How can I declare constant strings for use in both an unmanaged C++ dll and in a C# application?

    - by Surfbutler
    Curently I'm passing my const string values up from my C++ into my C# at startup via a callback, but I'm wondering if there's a way of defining them in a C++ header file that I can then also refer to in C#. I already do this with enums as they are easy. I include a file in both my C++ library project (via a .h file with a pragma once at the top), and my C# application (as a link): #if _NET public #endif enum ETestData { First, Second }; I know it sounds messy, but it works :) But...how can I do the same with string constants - I'm initially thinking the syntax is too different between the platforms, but maybe there's a way? Using clever syntax involving #if _NET, #defines etc? Using resource files? Using a C++/CLI library? Any ideas?

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  • Is it possible for a parent to use a child's constant or static variables from inside a static metho

    - by ryeguy
    Below is an example of what I'm trying to do. The parent can't access any of the child's variables. It doesn't matter what technique I use (static or constants), I just need some kind of functionality like this. class ParentClass { public static function staticFunc() { //both of these will throw a (static|const) not defined error echo self::$myStatic; echo self::MY_CONSTANT; } } class ChildClass extends ParentClass { const MY_CONSTANT = 1; public static $myStatic = 2; } ChildClass::staticFunc();

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  • How to convert int to char in JSP expression language?

    - by james.bunt
    I need to display incremented single characters to denote footnotes in a table of data in a JSP. In Java I would normally have a char variable and just increment it, or convert an int to a char by casting it (e.g. (char)(i + 97) to convert a 0-based index to a-z). I can't figure out how to do this in expression language short of writing my own JSTL function. Does anyone know how to convert an int to char in EL? Or how to increment a char variable in EL? Or possibly even a better technique to do what I'm trying to do in JSP/EL? Example of what I need to be able to produce: a mydata b myotherdata ... a first footnote b second footnote

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  • How do you match only valid roman numerals with a regular expression?

    - by Daniel Magliola
    Thinking about my other problem, i decided I can't even create a regular expression that will match roman numerals (let alone a context-free grammar that will generate them) The problem is matching only valid roman numerals. Eg, 990 is NOT "XM", it's "CMXC" My problem in making the regex for this is that in order to allow or not allow certain characters, I need to look back. Let's take thousands and hundreds, for example. I can allow M{0,2}C?M (to allow for 900, 1000, 1900, 2000, 2900 and 3000). However, If the match is on CM, I can't allow following characters to be C or D (because I'm already at 900). How can I express this in a regex? If it's simply not expressible in a regex, is it expressible in a context-free grammar? Thanks for any pointers!

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  • WPF: Is it possible to nest TreeView items with a binding expression?

    - by John Gietzen
    Lets say I have the following data: <XmlDataProvider x:Key="Values"> <x:XData> <folder name="C:"> <folder name="stuff" /> <folder name="things" /> <folder name="windows"> <folder name="system32" /> </folder> </folder> </x:XData> </XmlDataProvider> How can I get that into a treeview? I can't seem to grok hierarchical binding... I know that I can get it in there in C# code, but I wanted to do it with a binding expression.

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  • How do I get a value of a reference type in an Expression?

    - by Jon Kruger
    I have this method: public void DoSomething<T>(Expression<Func<T, object>> method) { } If this method is called like this: DoSomething(c => c.SomeMethod(new TestObject())); ... how do I get the value of the parameter that was passed into SomeMethod()? If the parameter is a value type, this works: var methodCall = (MethodCallExpression)method.Body; var parameterValue = ((ConstantExpression)methodCall.Arguments[0]).Value; However, when I pass in a reference type, methodCall.Arguments[0] is a MemberExpression, and I can't seem to figure out how to write code to get the value out of it.

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  • .Net Regular expression - how to do an exact match exclusion on a full string?

    - by Nathan Ridley
    I need a .Net regular expression that matches anything OTHER than the exact full string match specified. So basically: ^Index$ ... is the only exclusion I care about. Strings can start with, finish with or contain "Index", but not match exactly. My brain doesn't seem to be working today and I'm failing to work this one out. EDIT The answer MUST be via the pattern itself, as I am passing an argument to a third party library and do not have control over the process other than via the Regex pattern.

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  • Obj-C Error: Expected expression before ...... (why?)

    - by Horatiu Paraschiv
    Hi I have an enum declared like this: typedef enum { Top, Bottom, Center } UIItemAlignment; In my code I try to use it like this: item.alignment = UIItemAlignment.Top; I get an error like this: " Expected expression before 'UIItemAlignment' " If I use only: item.alignment = Top; everything works fine but why do I get this error if I try to use it the other way? _alignment is an NSInteger and it has a property declared like this @property (readwrite) NSInteger alignment; and I synthesized it in my implementation file. So my question is, why do I get this error?

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  • What regular expression do I need to check for some non-latin characters?

    - by zeckdude
    I am checking a field if it is Latin Characters or not. var foreignCharacters = $("#foreign_characters").val(); var rlatins = /[\u0000-\u007f]/; if (rlatins.test(foreignCharacters)) { alert("This is Latin Characters"); } else { alert("This is non-latin Characters"); } This works well, but I would like to change it so when I enter any non-latin characters, such as chinese characters, along with a space(which is within that range I am using currently) it will still say it is non-latin characters. How can I change the regular expression I have to do that?

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  • How can i filter a list of objects using lamda expression?

    - by Colour Blend
    I know i shouldn't have id's with the same value. This is just fictitious, so overlook that. I have: List<Car> carList = new List<Car>(); carList.Add(new Car() { id = 1, name = "Honda" }); carList.Add(new Car() { id = 2, name = "Toyota" }); carList.Add(new Car() { id = 1, name = "Nissan" }); I want to use Lamda Expression to retreive all cars that have an id of 1. Anticipated Result: -- Id: 1, Name: Honda -- Id: 1, Name: Nissan The problem is more filtering an object list based on a foriegn key. Please help me.

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  • How to use a regular expression and assign the result to variables in Android?

    - by ChengYing
    I have a string named s_Result which will be parsed from the Internet. The format may be "Distance: 2.8km (about 9 mins)", and there are 4 variables which are f_Distance, m_DistanceUnit, f_timeEst, m_timeEstUnit. My question is how to parse s_Result and assign 2.8, km, 9, mins into f_Distance, m_distanceUnit, f_timeEst and m_timeEstUnit respectively using regular expression? I tried using "\d+(\.\d+)?" in RegEx Tester and the result showed 2 matches found, but if I use "\\d+(\\.\\d+)?" in Android code, it showed no matches! Any suggestions what might be going wrong?

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  • How to customize $(project.compileClasspathElement) like expression in Maven?

    - by zbdiablo
    When i try to run a maven plugin, i found that the default classpath defined in expression $(project.compileClasspathElement) is too long. So, i just want to customize a shorter classpath for this plugin. The default configuration is as follows: <plugin> <groupId>org.datanucleus</groupId> <artifactId>maven-datanucleus-plugin</artifactId> <version>2.0.1</version> <configuration> ...<classpathElements>${project.compileClasspathElements}</classpathElements> </configuration> and the value of classpathElements should be a String List. May i solve this problem? and how? thx!

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  • How to use regular expression and assign result into valuables in Android??

    - by user304078
    Dear all, I have to say sorry for my poor English first... I have a string named s_Result which will be parsed from Internet, the format may be "Distance: 2.8km (about 9 mins)", and there are 4 variables which are f_Distance, m_DistanceUnit, f_timeEst, m_timeEstUnit. My question is, how to parse s_Result and assign 2.8, km, 9, mins into f_Distance, m_distanceUnit, f_timeEst, and m_timeEstUnit respectively using regular expression?? I tried using "\d+(.\d+)?" in RegEx Tester and the result showed 2 matches found, but if use "\\d+(\\.\\d+)?" in Android code, it showed nothing matched!!! Is there any suggestion?? Thanks for your help!!

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  • Why does this regular expression for sed break inside Makefile?

    - by jcrocholl
    I'm using GNU Make 3.81, and I have the following rule in my Makefile: jslint : java org.mozilla.javascript.tools.shell.Main jslint.js mango.js \ | sed 's/Lint at line \([0-9]\+\) character \([0-9]\+\)/mango.js:\1:\2/' This works fine if I enter it directly on the command line, but the regular expression does not match if I run it with "make jslint". However, it works if I replace \+ with \{1,\} in the Makefile: jslint : java org.mozilla.javascript.tools.shell.Main jslint.js mango.js \ | sed 's/Lint at line \([0-9]\{1,\}\) character \([0-9]\{1,\}\)/mango.js:\1:\2/' Is there some special meaning to \+ in Makefiles, or is this a bug?

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  • How to paste text and variables into a logical expression in R?

    - by Jasper
    I want to paste variables in the logical expression that I am using to subset data, but the subset function does not see them as column names when pasted (either with ot without quotes). I have a dataframe with columns named col1, col2 etc. I want to subset for the rows in which colx < 0.05 This DOES work: subsetdata<-subset(dataframe, col1<0.05) subsetdata<-subset(dataframe, col2<0.05) This does NOT work: for (k in 1:2){ subsetdata<-subset(dataframe, paste("col",k,sep="")<0.05) } for (k in 1:2){ subsetdata<-subset(dataframe, noquote(paste("col",k,sep=""))<0.05) } I can't find the answer; any suggestions?

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  • ASP.NET in VS IDE gives "Expression cannot be evaluated at this time."

    - by S Nash
    I read all of similar questions in SO but none seem to be an answer. Situation is simple. I have a ASP.NET webpage, In a VB code behind file I have the following line: iRendProvider = ddlProvider.SelectedItem.Value where iRendProvider is integer and ddlProvider is a dropdownlist. I put a breakpoint at the above line and code stops there. Now in the immdediate window in I type: ? ddlProvider.SelectedItem.Value I get "Expression cannot be evaluated at this time." If I step over iRendProvider = ddlProvider.SelectedItem.Value To the next line and I type ? iRendProvider , I see the correct value in the immediate window. Question is why this error and how to see contents of ddlProvider.

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  • how do i grab text of multiple tags in an xml feed using one xpath expression?

    - by Incognito
    Im trying to parse an xml feed that looks something like this: <item> <title>item title</title> <link>item link</link> <description>item description</description> </item> I'm trying to find an xpath expression that will retrieve all the details of each item so that each item in the feed is contained within its own array or grouped in some way. I tried using //item/* but the tags are not grouped, although they are correctly ordered. Is there anyway of doing that? edit: [ [title1, link1, desc1], [title2, link2, desc2], [title3, link3, desc3] ]

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  • Regular Expression to recognise truncated forms of search string?

    - by Moonshield
    I'm trying to formulate a regular expression which will recognise the search term truncated by any number of characters from the right. For example, if the search term is "pickle", the regex should recognise "pi", "pick" but not "pickaxe". Initially I came up with the following: p(i(c(k(l(e)?)?)?)?)? That works perfectly, but seems a crude way of doing it. Is there a better way of doing this? I had a look around for something similar to what I want, but I'm not entirely sure what to search for.

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  • Regular Expression; Find whether a line contains any word with more than X characters.

    - by Simpsoid
    Hi, I am trying to use a Validator on a ASP.NET site and need to find whether the Street Address textbox contains a valid entry. Entries with words that are longer than X characters (in this case 25, with no punctuation or spaces) will cause the HTML on a printed A4 page to not wrap properly and therefore not to confrom to certain sizes correctly pushing the margins off. For a street address I want to match that something like "201 Long Road" is valid but "235 ReallyLongAndNarrowWindingRoadBesideTheRiver Street" is invalid. Using a Microsoft .Net Regular Expression Validator I need to know what the RegEx pattern might be. I think if it does find a match the Validator will fire correctly however if there is no match the Validator won't fire and the Update button (in this case) won't fire. Since Street addresses can contain Capital Letters and numbers etc. it will need to accomodate for that and also Spaces, Commas, Semi-Colons and Colons and Hyphens are valid characters too. Any help would be greatly appreciated as I am really stuck with this problem. Thanks, David

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  • TypeError: Result of expression 'printWindow' [undefined] is not an object.

    - by orangebrainer
    I'm trying to create hidden iframes in my page dynamically to load 3 other pages so that i can grab all the HTML and combine them into 1 in a new window. However i'm stuck at this. tHe frames are created fine. But whenever the javascript runs to the part of function openNewWindow() { var printWindow = window.open("",""); printWindow.document.open(); printWindow.document.write(HTMLfromFrames); printWindow.document.close(); } i get this error: TypeError: Result of expression 'printWindow' [undefined] is not an object. but if i generate a button to call this function seperately, it works fine. however i need it to run all in one click event Anybody has any idea what's wrong? Thanks!

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  • Regular Expression to get the size value of a CSS property?

    - by thiesdiggity
    I wrote a regular expression to get the size from a CSS property: /(([+-]?\d*\.?\d+(\s)*(px|em|ex|pt|in|pc|mm|cm)?)|thin|medium|thick)(\s|;|$)/i but for some reason its not working as intended. For example, when I run the following: preg_match_all('/(([+-]?\d*\.?\d+(\s)*(px|em|ex|pt|in|pc|mm|cm)?)|thin|medium|thick)(\s|;|$)/i', "border-bottom:1px solid #99999;", $matches); It outputs: 1px 99999; But I only want the 1px value returned. I understand why its returning the above but can't seem to figure out how to only return the size and not the color value. I tried using the following negative lookbehind but it's not working either: /(((?<!#\d{3}|#\d{6})[+-]?\d*\.?\d+(\s)*(px|em|ex|pt|in|pc|mm|cm)?)|thin|medium|thick)(\s|;|$)/i I want to use preg_match_all for those CSS properties that can have multiple size values (i.e. margin). Anyone have any ideas how to get this regex to return only the size values? Thanks for your help!

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  • Get part of a string of part of regular expression?

    - by Buttink
    Im trying to make a script that will go into a directory and run my own application with each file matching a regular expression, specifically "Test[0-9]*.txt". My input filenames look like this "TestXX.txt". Now, I could just use cut and chop off the Test and .txt, but how would I do this if XX wasn't predefined to be 2 numbers? What would I do if i had "Test1.txt" ... "Test10.txt"? In other words, How would I get the [0-9]* part? Just so you know, I want to be able to make a OutputXX.txt :)

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