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  • How to split registration and media?

    - by Stackfan
    I have a SIP project. Where i will have SIP server running. Server will do following: will only do routing and receive incoming calls But the audio/video will be peer 2 peer Can this be done with Asterisk? Only the media i have to split but the registration will be with Server. Tools: A) server with SIP B) One PC with SIP client C) Anoher PC with SIP client My goal is: B and C gets connected via A and audio/video packets are not via A

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  • Software to Stream Media Content from Dedicated Server [closed]

    - by Christian
    We have Windows 2008 R2 Servers and we want to stream content (avi, wmv, mpeg etc) to Windows/Mac OS X/iOS etc devices. The visitor must be able to select the file (s)he want to view withing the library. We tried to accomplish this using: VLC Windows Media Service (WMS) Mediaportal VLC: We didnt find a solution to publish the content in a library WMS: only supports WMV/WMA, needs MediaPlayer MediaPortal: it is not supported on W2k8R2 Server Any suggestions? /chris

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  • Recovering from backup without original install media

    - by KGendron
    A machine from my old job had a complete hard drive failure. I have backups but I'm running into severe problems restoring from them. The only install media was a secondary restore partition on the system's hard drive. I hate whoever came up with that idea more than i can possibly express with words. I spent several days trying to recover the disk - it is pretty well shot and none of my best tricks could even get it to show up in the bios/ The machine that broke is an hp with xp media center edition on it (I don't know why either). The backups were created using the default windows backup tool - I have .bfk file on an external hardrive that i am trying to restore from. I've replaced the hard drive. My home machine is running windows 7 64bit and i'm trying to use it as a platform to restore to the other disk. I downloaded the window 7 nt-restore utility, however no matter what i do it restores to my C drive rather than the specified drive. Fortunately win7 security settings prevented it from being a complete disaster - but still not a happy thing. I tried firing up the xp virtual machine. I can browse to the backups but it says they are invalid and refuse to let me view/ continue with the restore. I tried installing XP to an extra harddrive on my machine - however it bluescreens on me during the install process and I cry. I tried installing xp pro to the new drive and attempted to restore over it, it of course blackscreened on me as that was a stupid idea. I made two partitions on the new hard drive (Apparently the bios on this accursed piece of junk doesn't allow hd partitions larger than 200G anyways and thus fails 40 minutes into the install with an ever-descriptive "Disk Read Error". Guess how i spent last weekend? My last idea was to install xp pro to the second partition and then use it to restore from backup to the first. After the first restart it gives me the error "Windows could not start because of a computer disk hardware configuration problem. Could not read from the selected boot disk. Check boot path and disk hardware". My brain made one of those bad hard drive clicky noises. I've tried several boot disks but they don't seem to work. If anyone has a link to a good one it would be greatly appreciated. Anyone have any more ideas? - I really hate asking on what seems like such a simple issue but i am quite literally at my wit's end. Thanks - and sorry for the really long post.

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  • Moving media files while preserving itunes rating

    - by akurtser
    Hi, I've seen many threads on how to move an entire media collection from one machine to another. I want to organize my mp3 directories, but any copied file loses its reference from itunes library, thus, when I add it to itunes again, it'll have no rating data. I guess it's possible if I manipulate the itunes xml database, but I really don't want to mess with it "by hand".

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  • Media meta file system for windows

    - by Chris Marisic
    I have a large assortment of media that is currently arranged using folders. As the library has grown I've started to notice that folders aren't the best at conveying meaning. Also as the number of folders serving as categories/tags has grown has lead to data duplication for not realizing it was already filed under a different tag. As I started to think about this I realized tag cloud visualization would be tremendously powerful and figured there has to be something like this out there.

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  • using git for media libraries

    - by mpapis
    Rationale: I want to manage libraries of media files (music, images) using git, there is git-annex but it requires haskel platform - but they do not play together well (also it's quite to big dependency for me). Question: Is there any other plugin with this functionality, or possibly would it be possible to write such plugin (resources?). Similar questions: Self-hosted, cross-platform repository for large files Using Git to Manage An iTunes Library?

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  • Windows XP MCE (Media Center)

    - by Kev
    Hi, I have Media Center installed on my PC. I hardly use it but once in a while I notice that its taking up gigs and gigs of space...which is due to the fact that it auto-"magically" starts recording shows on its own. Since I never set up any recording, I am wondering how to disable this. Thanks.

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  • ERROR! (Using Excel's named ranges from C#)

    - by mcoolbeth
    In the following, I am trying to persist a set of objects in an excel worksheet. Each time the function is called to store a value, it should allocate the next cell of the A column to store that object. However, an exception is thrown by the Interop library on the first call to get_Range(). (right after the catch block) Does anyone know what I am doing wrong? private void AddName(string name, object value) { Excel.Worksheet jresheet; try { jresheet = (Excel.Worksheet)_app.ActiveWorkbook.Sheets["jreTemplates"]; } catch { jresheet = (Excel.Worksheet)_app.ActiveWorkbook.Sheets.Add(Type.Missing, Type.Missing, Type.Missing, Type.Missing); jresheet.Visible = Microsoft.Office.Interop.Excel.XlSheetVisibility.xlSheetVeryHidden; jresheet.Name = "jreTemplates"; jresheet.Names.Add("next", "A1", true, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing); } Excel.Range cell = jresheet.get_Range("next", Type.Missing); cell.Value2 = value; string address = ((Excel.Name)cell.Name).Name; _app.ActiveWorkbook.Names.Add(name, address, false, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing); cell = cell.get_Offset(1, 0); jresheet.Names.Add("next", ((Excel.Name)cell.Name).Name, true, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing); }

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  • WordPress contact form email as PDF

    - by lock
    I am using the below code for my WordPress site which is emailing all the form details as an HTML text but I need the details to be written into a PDF first and then have to email the PDF as an attachment. How can I achieve this? This is not a PHP code to use PHP's writePDF modules. So, any idea or any code to implement this? <div style="padding-left: 100px;"> [raw] [contact-form subject="Best Aussie Broker" to="[email protected]"] <div id="main34" style="border: 1px solid black; border-radius: 15px; width: 720px; padding: 15px;"> &nbsp; <h2><span style="color: #ff6600;">Express Application</span></h2> &nbsp; [contact-field label="First Name" type="name" required="true" /] [contact-field label="Last Name" type="text" /] [contact-field label="Email" type="email" required="true" /] [contact-field label="Purpose of Finance?" type="select" options="Home Loan,Refinance,Investment Loan,Debt Consolidation,Other" /] [contact-field label="Your deposit amount" type="text" /] [contact-field label="Amount you need to borrow?" type="text" /] [contact-field label="Brief description of the purpose for finance" type="textarea" required="true" /] <div><label></label> <input class="radio" type="radio" name="19" value="Single Application" onchange="showsingle();" /> <label class="radio">Single Application</label> <div class="clear-form"></div> <input class="radio" type="radio" name="19" value="Joint Application" onchange="showjoint();" /> <label class="radio">Joint Application</label> <div class="clear-form"></div> [contact-field label="Privacy Act" type="checkbox" required="true" /] I have read the Privacy Act 1988 (as Amended) and understand that by selecting the submit button I/we Authorize Best Aussie Broker to act on my/our behalf and manage personal information in relation to this application.<br> <a href="http://googleplex.com.au/pdf.pdf"><img src="http://googleplex.com.au/pdf.png" alt="" /> </a> </div> </div> <div id="single" style="display: none; width: 720px; border: 1px solid black; border-radius: 15px; padding: 15px; margin-top: 10px;"> <div style="padding-top: 10px; width: 720px; text-align: left;"> <h4><span style="color: #ff6600;">Last step then we will get all listed Australian vendors to fight it out for your best deal</span></h4> </div> <div> <label class="select" for="19-date-of-birth">Date of Birth</label> [contact-field label="Day" type="select" options="1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31" /] [contact-field label="Month" type="select" options="January,February,March,April,May,June,July,August,September,October,November,December" /] [contact-field label="Year" type="select" options="2000,1999,1998,1997,1996,1995,1994,1993,1992,1991,1990,1989,1988,1987,1986,1985,1984,1983,1982,1981,1980,1979,1978,197,1976,1975,1974,1973,1972,1971,1970,1969,1968,1967,1966,1965,1964,1963,1962,1961,1960,1959,1958,1957,1956,1955,1954,1953,1952,1951,1950,1949,1948,1947,1946,1945,1944,1943,1942,1941,1940,1939,1938,1937,1936,1935,1934,1933,1932,1931,1930,1929,1928,1927,1926,1925,1924,1923,1922,1921,1920, 1919,1918,1917,1916,1915,1914,1913,1912,1911,1910,1909" /] </div> [contact-field label="Address" type="text" /] [contact-field label="Suburb" type="text" /] [contact-field label="Postcode" type="text" /] <div> [contact-field label="State" type="select" options="VIC,NSW,QLD,SA,WA,TAS,NZ,Other" /] </div> [contact-field label="Best Contact" type="radio" options="Landline,Mobile" /] [contact-field label="Phone Number" type="text" /] [contact-field label="Marital Status" type="select" options="Married,Single,Other" /] [contact-field label="Residential Status" type="select" options="Renting, Home Owned, Home Mortgage, Board, Other" /] [contact-field label="Children/Dependents" type="select" options="0,1,2,3,4,5,6" /] <div></div> [contact-field label="Gross Yearly Income" type="text" /] [contact-field label="Current Employer" type="text" /] <div> <label class="select" for="19-year-of-empl">Time at this employer</label> [contact-field label="Year" type="select" options="0,1,2,3,4,5,6,7,8,9,10,More" /] [contact-field label="Month" type="select" options="0,1,2,3,4,5,6,7,8,9,10,11,12" /] </div> <div style="padding-right: 15px;"></div> </div> <div id="joint" style="display: none; width: 720px; border: 1px solid black; border-radius: 15px; padding: 15px; margin-top: 10px;"> <div style="padding-top: 10px; width: 720px; text-align: left;"> <h4><span style="color: #ff6600;">Last step then we will get all listed Australian vendors to fight it out for your best deal</span></h4> </div> <div style="float: left; width: 320px;"> <div> <label class="select" for="19-date-of-birth1">Date of Birth</label> [contact-field label="Day" type="select" options="1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31" /] [contact-field label="Month" type="select" options="January,February,March,April,May,June,July,August,September,October,November,December" /] [contact-field label="Year" type="select" options="2000,1999,1998,1997,1996,1995,1994,1993,1992,1991,1990,1989,1988,1987,1986,1985,1984,1983,1982,1981,1980,1979,1978,197,1976,1975,1974,1973,1972,1971,1970,1969,1968,1967,1966,1965,1964,1963,1962,1961,1960,1959,1958,1957,1956,1955,1954,1953,1952,1951,1950,1949,1948,1947,1946,1945,1944,1943,1942,1941,1940,1939,1938,1937,1936,1935,1934,1933,1932,1931,1930,1929,1928,1927,1926,1925,1924,1923,1922,1921,1920, 1919,1918,1917,1916,1915,1914,1913,1912,1911,1910,1909" /] </div> [contact-field label="Address" type="text" /] [contact-field label="Suburb" type="text" /] [contact-field label="Postcode" type="text" /] <div> [contact-field label="State" type="select" options="VIC,NSW,QLD,SA,WA,TAS,NZ,Other" /] </div> [contact-field label="Best Contact" type="radio" options="Landline,Mobile" /] [contact-field label="Phone Number" type="text" /] <div></div> <div></div> [contact-field label="Marital Status" type="select" options="Married,Single,Other" /] [contact-field label="Residential Status" type="select" options="Renting, Home Owned, Home Mortgage, Board, Other" /] [contact-field label="Children/Dependents" type="select" options="0,1,2,3,4,5,6" /] <div></div> <div><label class="text" for="netincome">Net Income</label> <input id="netincome" type="text" name="netincome" /> <select id="netincome-dropdown" name="netincome-dropdown"> <option>Monthly</option> <option>Yearly</option> </select></div> [contact-field label="Current Employer" type="text" /] <div> <label class="select" for="19-year-of-empl2">Time at this employer</label> [contact-field label="Year" type="select" options="0,1,2,3,4,5,6,7,8,9,10,More" /] [contact-field label="Month" type="select" options="0,1,2,3,4,5,6,7,8,9,10,11,12" /] </div> </div> <div style="float: right; width: 320px; padding-right: 50px;"> <div> <label class="select" for="19-date-of-birth3">Date of Birth</label> [contact-field label="Day" type="select" options="1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31" /] [contact-field label="Month" type="select" options="January,February,March,April,May,June,July,August,September,October,November,December" /] [contact-field label="Year" type="select" options="2000,1999,1998,1997,1996,1995,1994,1993,1992,1991,1990,1989,1988,1987,1986,1985,1984,1983,1982,1981,1980,1979,1978,197,1976,1975,1974,1973,1972,1971,1970,1969,1968,1967,1966,1965,1964,1963,1962,1961,1960,1959,1958,1957,1956,1955,1954,1953,1952,1951,1950,1949,1948,1947,1946,1945,1944,1943,1942,1941,1940,1939,1938,1937,1936,1935,1934,1933,1932,1931,1930,1929,1928,1927,1926,1925,1924,1923,1922,1921,1920, 1919,1918,1917,1916,1915,1914,1913,1912,1911,1910,1909" /] </div> [contact-field label="Address" type="text" /] [contact-field label="Suburb" type="text" /] [contact-field label="Postcode" type="text" /] <div> [contact-field label="State" type="select" options="VIC,NSW,QLD,SA,WA,TAS,NZ,Other" /] </div> [contact-field label="Best Contact" type="radio" options="Landline,Mobile" /] [contact-field label="Phone Number" type="text" /] <div></div> <div></div> [contact-field label="Marital Status" type="select" options="Married,Single,Other" /] [contact-field label="Residential Status" type="select" options="Renting, Home Owned, Home Mortgage, Board, Other" /] [contact-field label="Children/Dependents" type="select" options="0,1,2,3,4,5,6" /] <div></div> <div><label class="text" for="netincome">Net Income</label> <input id="netincome" type="text" name="netincome" /> <select id="netincome-dropdown" name="netincome-dropdown"> <option>Monthly</option> <option>Yearly</option> </select></div> [contact-field label="Current Employer" type="text" /] <div> <label class="select" for="19-year-of-empl">Time at this employer</label> [contact-field label="Year" type="select" options="0,1,2,3,4,5,6,7,8,9,10,More" /] [contact-field label="Month" type="select" options="0,1,2,3,4,5,6,7,8,9,10,11,12" /] </div> </div> <div style="clear: both;"></div> <div></div> </div> &nbsp; [/contact-form][/raw] </div>

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  • WCF: collection proxy type on client

    - by Unholy
    I have the following type in wsdl (it is generated by third party tool): <xsd:complexType name="IntArray"> <xsd:sequence> <xsd:element maxOccurs="unbounded" minOccurs="0" name="Elements" type="xsd:int" /> </xsd:sequence> </xsd:complexType> Sometimes Visual Studio generates: public class IntArray : System.Collections.Generic.List<int> {} And sometimes it doesn't generate any proxy type for this wsdl and just uses int[]. Collection type in Web Service configuration is System.Array. What could be the reason for such upredictable behavior? Edited: I found the way how I can reproduce this behavior. For examle we have two types: <xsd:complexType name="IntArray"> <xsd:sequence> <xsd:element maxOccurs="unbounded" minOccurs="0" name="Elements" type="xsd:int" /> </xsd:sequence> </xsd:complexType> <xsd:complexType name="StringArray"> <xsd:sequence> <xsd:element maxOccurs="unbounded" minOccurs="0" name="Elements" type="xsd:string" /> </xsd:sequence> </xsd:complexType> VS generates: public class IntArray : System.Collections.Generic.List<int> {} public class StringArray : System.Collections.Generic.List<string> {} Now I change StringArray type: <xsd:complexType name="StringArray"> <xsd:sequence> <xsd:element maxOccurs="unbounded" minOccurs="0" name="Elements" type="xsd:string" /> <xsd:any minOccurs="0" maxOccurs="unbounded" namespace="##any" processContents="lax" /> </xsd:sequence> <xsd:anyAttribute namespace="##any" processContents="lax"/> </xsd:complexType> VS generates proxy type for StringArray only. But not for IntArray.

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  • Template specialization to use default type if class member typedef does not exist

    - by Frank
    Hi Everyone, I'm trying to write code that uses a member typedef of a template argument, but want to supply a default type if the template argument does not have that typedef. A simplified example I've tried is this: struct DefaultType { DefaultType() { printf("Default "); } }; struct NonDefaultType { NonDefaultType() { printf("NonDefault "); } }; struct A {}; struct B { typedef NonDefaultType Type; }; template<typename T, typename Enable = void> struct Get_Type { typedef DefaultType Type; }; template<typename T> struct Get_Type< T, typename T::Type > { typedef typename T::Type Type; }; int main() { Get_Type::Type test1; Get_Type::Type test2; } I would expect this to print "Default NonDefault", but instead it prints "Default Default". My expectation is that the second line in main() should match the specialized version of Get_Type, because B::Type exists. However, this does not happen. Can anyone explain what's going on here and how to fix it, or another way to accomplish the same goal? Thank you.

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  • Using Shell32 to extract Mimes on Windows Server 2008

    - by Léon Pelletier
    In a desktop app, I'm using Shell32 to extract Mime infos and ID3 tags. I want to do the same in ASP.Net on server side with http posted files, plus fetch some other infos, but as a Windows Server 2008, there are not several media applications installed, so I wonder if it will still retrieve a lot of informations from the files. Will it be possible to do it from server side? If yes, will it fetch several Mimes without media app installed. If not, is there some Mime pack to get some file informations without the app being installed. [EDIT] I installed VLC player and Windows Media Player on the server, which provide all MP3s / movies infos (Duration, Artist, Album, Width, Height, etc.), but I don't know if this is a good practice.

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  • Java generic return type

    - by Colby77
    Hi, I'd like to write a method that can accept a type param (or whatever the method can figure out the type from) and return a value of this type so I don't have to cast the return type. Here is a method: public Object doIt(Object param){ if(param instanceof String){ return "string"; }else if(param instanceof Integer){ return 1; }else{ return null; } } When I call this method, and pass in it a String, even if I know the return type will be a String I have to cast the return Object. This is similar to the int param. How shall I write this method to accept a type param, and return this type?

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  • jQuery plugin, return value from function

    - by Marius
    Hello there, Markup: <input type="text" name="email" /> Code: $(':text').focusout(function(){ $(this).validate(function(){ $(this).attr('name'); }); }); Plugin: (function($){ $.fn.validate = function(type) { return this.each(function(type) { if (type == 'email') { matches = this.val().match('/.+@.+\..{2,7}/'); (matches != null) ? alert('valid') : alert('invalid'); } /*else if (type == 'name') { } else if (type == 'age') { } else if (type == 'text') { }*/ else { alert('total failure'); } }); }; })(jQuery); The problem is that when I execute the code above, it runs the plugin as if type was a string: "function(){ $(this).attr('name'); });" instead of executing it as a function. How do I solve this? Thank you for your time. Kind regards, Marius

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  • ActionScript: Type coercion problem with BlazeDS/AMF and class interfaces

    - by mike
    Hi, I've got a problem with type coercion in a Java/Hibernate/BlazeDS/Flex-Setup. First of all, my classes look like this: --- JAVA --- Interface I (Abstract) Class A implements I Class B extends A --- ActionScript --- Interface I Class A implements I Class B extends A I got RemoteClass-Meta-Tags in all ActionScript-Classes/Interfaces I, A and B. Package structure and Class/Interface names are exactly the same. Now here's the problem: My Java Service successfully retrieves objects of class B from my database via Hibernate. I got another class C which has a member property of interface type I, so it should be possible to assign an object of type B. But for some reason i get the following error message: TypeError: Error #1034: cannot convert Object@28b44a89 to package.name.I I checked the Java object type in the service and it is of type B and seems to be totally fine. Why can't the object of type B be assigned to a member variable of type I? This is driving me nuts. Thanks in advance.

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  • Self-type mismatch in Scala

    - by Alexey Romanov
    Given this: abstract class ViewPresenterPair { type V <: View type P <: Presenter trait View {self: V => val presenter: P } trait Presenter {self: P => var view: V } } I am trying to define an implementation in this way: case class SensorViewPresenter[T] extends ViewPresenterPair { type V = SensorView[T] type P = SensorPresenter[T] trait SensorView[T] extends View { } class SensorViewImpl[T](val presenter: P) extends SensorView[T] { presenter.view = this } class SensorPresenter[T] extends Presenter { var view: V } } Which gives me the following errors: error: illegal inheritance; self-type SensorViewPresenter.this.SensorView[T] does not conform to SensorViewPresenter.this.View's selftype SensorViewPresenter.this.V trait SensorView[T] extends View { ^ <console>:13: error: type mismatch; found : SensorViewPresenter.this.SensorViewImpl[T] required: SensorViewPresenter.this.V presenter.view = this ^ <console>:16: error: illegal inheritance; self-type SensorViewPresenter.this.SensorPresenter[T] does not conform to SensorViewPresenter.this.Presenter's selftype SensorViewPresenter.this.P class SensorPresenter[T] extends Presenter { ^ I don't understand why. After all, V is just an alias for SensorView[T], and the paths are the same, so how can it not conform?

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  • Undetermined type conversion in VB.NET 2008

    - by user337501
    I figured this would be a quick google, but extensive searching hasnt yielded any results. Everything about type conversion seems to dance around this concept. I want to get the type of variable "a", and make a new variable named "b" of that type. Otherwise I could have "a" as a type already declared and "b" simply as an Object, then try to cast "b" to the type of "a". Dim a As Integer Dim b As Whatever a Is OR TryCast(b, Whatever a Is) I would also like to make the conversion using a variable representation of the type, but cant find info on how to do that either. Sorta like: Dim a As Integer Dim b As Object Dim t As Type t = a.GetType() TryCast(b, t) Realizing I'm completely misusing TryCast here, I'm mostly trying to get my goal across. I figured it would be an easy quick thing to do but I cant really find any specific info on it. Any ideas?

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  • How to properly translate the "var" result of a lambda expression to a concrete type?

    - by CrimsonX
    So I'm trying to learn more about lambda expressions. I read this question on stackoverflow, concurred with the chosen answer, and have attempted to implement the algorithm using a console app in C# using a simple LINQ expression. My question is: how do I translate the "var result" of the lambda expression into a usable object that I can then print the result? I would also appreciate an in-depth explanation of what is happening when I declare the outer => outer.Value.Frequency (I've read numerous explanations of lambda expressions but additional clarification would help) C# //Input : {5, 13, 6, 5, 13, 7, 8, 6, 5} //Output : {5, 5, 5, 13, 13, 6, 6, 7, 8} //The question is to arrange the numbers in the array in decreasing order of their frequency, preserving the order of their occurrence. //If there is a tie, like in this example between 13 and 6, then the number occurring first in the input array would come first in the output array. List<int> input = new List<int>(); input.Add(5); input.Add(13); input.Add(6); input.Add(5); input.Add(13); input.Add(7); input.Add(8); input.Add(6); input.Add(5); Dictionary<int, FrequencyAndValue> dictionary = new Dictionary<int, FrequencyAndValue>(); foreach (int number in input) { if (!dictionary.ContainsKey(number)) { dictionary.Add(number, new FrequencyAndValue(1, number) ); } else { dictionary[number].Frequency++; } } var result = dictionary.OrderByDescending(outer => outer.Value.Frequency); // How to translate the result into something I can print??

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  • Make interchangeable class types via pointer casting only, without having to allocate any new objects?

    - by HostileFork
    UPDATE: I do appreciate "don't want that, want this instead" suggestions. They are useful, especially when provided in context of the motivating scenario. Still...regardless of goodness/badness, I've become curious to find a hard-and-fast "yes that can be done legally in C++11" vs "no it is not possible to do something like that". I want to "alias" an object pointer as another type, for the sole purpose of adding some helper methods. The alias cannot add data members to the underlying class (in fact, the more I can prevent that from happening the better!) All aliases are equally applicable to any object of this type...it's just helpful if the type system can hint which alias is likely the most appropriate. There should be no information about any specific alias that is ever encoded in the underlying object. Hence, I feel like you should be able to "cheat" the type system and just let it be an annotation...checked at compile time, but ultimately irrelevant to the runtime casting. Something along these lines: Node<AccessorFoo>* fooPtr = Node<AccessorFoo>::createViaFactory(); Node<AccessorBar>* barPtr = reinterpret_cast< Node<AccessorBar>* >(fooPtr); Under the hood, the factory method is actually making a NodeBase class, and then using a similar reinterpret_cast to return it as a Node<AccessorFoo>*. The easy way to avoid this is to make these lightweight classes that wrap nodes and are passed around by value. Thus you don't need casting, just Accessor classes that take the node handle to wrap in their constructor: AccessorFoo foo (NodeBase::createViaFactory()); AccessorBar bar (foo.getNode()); But if I don't have to pay for all that, I don't want to. That would involve--for instance--making a special accessor type for each sort of wrapped pointer (AccessorFooShared, AccessorFooUnique, AccessorFooWeak, etc.) Having these typed pointers being aliased for one single pointer-based object identity is preferable, and provides a nice orthogonality. So back to that original question: Node<AccessorFoo>* fooPtr = Node<AccessorFoo>::createViaFactory(); Node<AccessorBar>* barPtr = reinterpret_cast< Node<AccessorBar>* >(fooPtr); Seems like there would be some way to do this that might be ugly but not "break the rules". According to ISO14882:2011(e) 5.2.10-7: An object pointer can be explicitly converted to an object pointer of a different type.70 When a prvalue v of type "pointer to T1" is converted to the type "pointer to cv T2", the result is static_cast(static_cast(v)) if both T1 and T2 are standard-layout types (3.9) and the alignment requirements of T2 are no stricter than those of T1, or if either type is void. Converting a prvalue of type "pointer to T1" to the type "pointer to T2" (where T1 and T2 are object types and where the alignment requirements of T2 are no stricter than those of T1) and back to its original type yields the original pointer value. The result of any other such pointer conversion is unspecified. Drilling into the definition of a "standard-layout class", we find: has no non-static data members of type non-standard-layout-class (or array of such types) or reference, and has no virtual functions (10.3) and no virtual base classes (10.1), and has the same access control (clause 11) for all non-static data members, and has no non-standard-layout base classes, and either has no non-static data member in the most-derived class and at most one base class with non-static data members, or has no base classes with non-static data members, and has no base classes of the same type as the first non-static data member. Sounds like working with something like this would tie my hands a bit with no virtual methods in the accessors or the node. Yet C++11 apparently has std::is_standard_layout to keep things checked. Can this be done safely? Appears to work in gcc-4.7, but I'd like to be sure I'm not invoking undefined behavior.

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  • Does this code describe an Existential Type in C#?

    - by noblethrasher
    Currently watching Bart De Smet's explanation of IQueryable and he mentioned Existential Types (which I've been curious about for some time). After reading the answers to this question I'm just wondering if this is a way to construct it in C#: public abstract class ExistentialType { private ExistentialType() { } public abstract int Foo(); public ExistentialType Create() { return new ConcreateType1(); } private class ConcreateType1 : ExistentialType { public override int Foo() { throw new NotImplementedException(); } } private class ConcreateType2 : ExistentialType { public override int Foo() { throw new NotImplementedException(); } } private class ConcreateType3 : ExistentialType { public override int Foo() { throw new NotImplementedException(); } } }

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  • How does c# type safety affect the garbage collection?

    - by Indeera
    I'm dealing with code that handles large buffers ( 100MB) and manipulation of these is done in unsafe blocks. I'd like to refactor these to avoid unsafe code. I'm wondering about the likely memory performance gains (positive/negative/neutral) before I embark on that. I assert that if the compiler can verify types, it could possibly generate better code and that could also mean good GC performance. Is this a valid assertion? What is your experience? Thanks.

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  • Type signature "Maybe a" doesn't like "Just [Event]"

    - by sisif
    I'm still learning Haskell and need help with the type inference please! Using packages SDL and Yampa I get the following type signature from FRP.Yampa.reactimate: (Bool -> IO (DTime, Maybe a)) and I want to use it for: myInput :: Bool -> IO (DTime, Maybe [SDL.Event]) myInput isBlocking = do event <- SDL.pollEvent return (1, Just [event]) ... reactimate myInit myInput myOutput mySF but it says Couldn't match expected type `()' against inferred type `[SDL.Event]' Expected type: IO (DTime, Maybe ()) Inferred type: IO (DTime, Maybe [SDL.Event]) In the second argument of `reactimate', namely `input' In the expression: reactimate initialize input output process I thought Maybe a allows me to use anything, even a SDL.Event list? Why is it expecting Maybe () when the type signature is actually Maybe a? Why does it want an empty tuple, or a function taking no arguments, or what is () supposed to be?

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  • (newbie) type signature "Maybe a" doesn't like "Just [Event]"

    - by sisif
    i'm still learning Haskell and need help with the type inference please! using packages SDL and Yampa i get the following type signature from FRP.Yampa.reactimate: (Bool -> IO (DTime, Maybe a)) and i want to use it for: myInput :: Bool -> IO (DTime, Maybe [SDL.Event]) myInput isBlocking = do event <- SDL.pollEvent return (1, Just [event]) ... reactimate myInit myInput myOutput mySF but it says Couldn't match expected type `()' against inferred type `[SDL.Event]' Expected type: IO (DTime, Maybe ()) Inferred type: IO (DTime, Maybe [SDL.Event]) In the second argument of `reactimate', namely `input' In the expression: reactimate initialize input output process i thought "Maybe a" allows me to use anything, even a SDL.Event list? why is it expecting "Maybe ()" when the type signature is actually "Maybe a"? why does it want an empty tuple, or a function taking no arguments, or what is () supposed to be?

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