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Search found 1870 results on 75 pages for 'reinterpret cast'.

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  • Solving C++ 'target of assignment not really an lvalue' errors

    - by Jason
    Given this code: void FrMemCopy(void *to, const void *from, size_t sz) { size_t sz8 = sz >> 3; size_t sz1 = sz - (sz8 << 3); while (sz8-- != 0) { *((double *)to)++ = *((double *)from)++; } while (sz1-- != 0) { *((char *)to)++ = *((char *)from)++; } } I am receiving target of assignment not really an lvalue warnings on the 2 lines inside the while loops. Can anyone break down those lines? a cast then an increment? What is a simplier way to write that? What does the error mean?

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  • Unboxing object containing a value which is known to be assignable to an integer variable

    - by Wim Coenen
    If I have an object instance and I know it is actually a boxed integer, then I can simply cast it back to int like this: object o = GetSomethingByName("foo"); int i = (int)o; However, I don't actually know that the value is an integer. I only know that it can be assigned to an integer. For example, it could be a byte, and the above code would throw InvalidCastException in that case. Instead I would have to do this: object o = GetSomethingByName("foo"); int i = (int)(byte)o; The value could also be a short, or something else which can be assigned to an int. How do I generalize my code to handle all those cases (without handling each possibility separately)?

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  • are Hierarchical SIngletons in Java possible?

    - by Zach H
    I've been toying with an interesting idea (No idea if I'll include it in any code, but it's fun to think about) Let's say we have a program that requires a large number of classes, all of a certain subclass. And those classes all need to be singletons. Now, we could write the singleton pattern for each of those classes, but it seems wasteful to write the same code over and over, and we already have a common base class. It would be really nice to create a getSingleton method of A that when called from a subclass, returns a singleton of the B class (cast to class A for simplicity) class A{ public A getSingleton(){ //Wizardry } } class B extends A{ } A blargh = B.getSingleton() A gish = B.getSingleton() if(A == B) System.out.println("It works!") It seems to me that the way to do this would be to recognize and call B's default constructor (assuming we don't need to pass anything in.) I know a little of the black magic of reflection in Java, but i'm not sure if this can be done. Anyone interested in puzzling over this?

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  • Converting c++ string to int

    - by skazhy
    Hi! I have the following data in a c++ string John Doe 01.01.1970 I need to extract the date and time from it into int variables. I tried it like this: int last_space = text_string.find_last_of(' '); int day = int(text_string.substr(last_space + 1, 2)); But I got invalid cast from type ‘std::basic_string’ to type ‘int’. When I extract the "John Doe" part in another string variable, all works fine. What's wrong? I am trying to compile it with g++ -Wall -Werror.

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  • How to print size_t variable portably?

    - by ArunSaha
    I have a variable of type size_t, and I want to print it using printf(). What format specifier do I use to print it portably? In 32-bit machine, %u seems right. I compiled with g++ -g -W -Wall -Werror -ansi -pedantic, and there was no warning. But when I compile that code in 64-bit machine, it produces warning. size_t x = <something>; printf( "size = %u\n", x ); warning: format '%u' expects type 'unsigned int', but argument 2 has type 'long unsigned int' The warning goes away, as expected, if I change that to %lu. The question is, how can I write the code, so that it compiles warning free on both 32- and 64- bit machines? Edit: I guess one answer might be to "cast" the variable into an unsigned long, and print using %lu. That would work in both cases. I am looking if there is any other idea. (C, C++)

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  • Hex to bin after logical operations

    - by user355926
    I want: 111 || 100 ---> 111, not 1 100 && 100 ---> 100, not 1 101 && 010 ---> 000, not 0 Broken code #include <stdio.h> main(void){ string hexa = 0xff; strig hexa2 = 0xf1; // CONVERT TO INT??? cast int hexa3 = hexa || hexa2; int hexa4 = hexa && hexa2; puts(hexa3); puts(hexa4); }

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  • c# 4.0 - best way to refactor a block of "If (something is Type) {}" statements?

    - by Andrew Johns
    I've got some code that looks like this, public void ResetControls(Control controlOnPage) { if (controlOnPage is TextBox) { ResetTextBoxControl(controlOnPage); } if (controlOnPage is MediaPicker) { ((MediaPicker)controlOnPage).Media = null; } if (controlOnPage is RelatedContentPicker) { ((RelatedContentPicker)controlOnPage).RelatedContentCollection = null; } ... ... foreach (Control child in controlOnPage.Controls) { ResetControls(child); } } The idea behind it is that I can pass a page to the method and it'll recursively reset all the controls on it to their default states - in the case of MediaPicker and RelatedContentPicker, these are user controls that I've created. FXCop warns me "Do Not Cast Unnecessarily" for this code - but I'm unsure how to rewrite it to make it better. Any ideas?

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  • So I dynamically load a jar at runtime how do I use it?

    - by justinhj
    So question 194698 shows how to load a jar file at runtime and you can load individual named classes and get a Class object. Now my problem is I want to be able to cast those Classes to the types they really are, but I can't because I can't use an import since the whole point is to load it at runtime rather than compile time. It seems like the way to go is to use reflection to discover the functions and field names, but that seems brittle since the API in the jar files could change and the code won't break until it is run. Is there a better way?

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  • Container<ImplementerOfIInterface> is not Container<IInterface>. Why not?

    - by Chris Simmons
    Why wouldn't DoesntWork() work below? The error is: Cannot implicitly convert type 'List' to 'IEnumerable'. An explicit conversion exists (are you missing a cast?). I know this is something about generic/templates I'm not getting, but List is IEnumerable and Implementer is an IInterface. I don't see why this needs to be casted (or if it really can be). public interface IInterface { // ... } public class Implementer : IInterface { // ... } IEnumerable<IInterface> DoesntWork() { List<Implementer> result = new List<Implementer>(); return result; }

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  • Asp.Net - Can a LinkButton.CommandArgument be typed?

    - by Stimul8d
    Okay so given a LinkButton inside a the ItemTemplate of a Repeater declared like this - <asp:LinkButton ID="restrictionDelete" runat="server" CssClass="restrictionDelete" Text="Delete..." OnCommand="lnkDeleteRestriction_Command" CommandName="Delete" CommandArgument="<%# Container.DataItem %>"></asp:LinkButton> Now,..the repeater is being bound to a list of Restriction objects so when the lnkDeleteRestriction_Command is fired I'm expecting that I can cast the CommandEventArgs.CommandArgument which is an object to my Restriction type. This doesn't seem to be so,..I just get the fully qualified type name as a string. Can I receive a typed command argument at all and if not, why is it an object? Thanks in advance,

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  • Determine an object's class returned by a factory method (Error: function does not take 1 arguments

    - by tzippy
    I have a factorymethod that either returns an object of baseclass or one that is of derivedclass (a derived class of baseclass). The derived class has a method virtual void foo(int x) that takes one argument. baseclass however has virtual void foo() without an argument. In my code, a factory method returns a pointer of type bar that definetly points to an object of class derivedclass. However since this is only known at runtime I get a compiler error saying that foo() does not take an argument. Can I cast this pointer to a pointer of type derivedclass? std::auto_ptr<baseclass> bar = classfactory::CreateBar(); //returns object of class derivedclass bar->foo(5); class baseclass { public: virtual void foo(); } class derivedclass : public baseclass { public: virtual void foo(int x); }

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  • C++/CLI and C#, "Casting" Functions to Delegates, What's the scoop?

    - by Jacob G
    In C# 2.0, I can do the following: public class MyClass { delegate void MyDelegate(int myParam); public MyClass(OtherObject obj) { //THIS IS THE IMPORTANT PART obj.SomeCollection.Add((MyDelegate)MyFunction); } private void MyFunction(int myParam); { //... } } Trying to implement the same thing in C++/CLI, it appears I have to do: MyDelegate del = gcnew MyDelegate(this, MyFunction); obj-SomeCollection-Add(del); Obviously I can create a new instance of the delegate in C# as well instead of what's going on up there. Is there some kind of magic going on in the C# world that doesn't exist in C++/CLI that allows that cast to work? Some kind of magic anonymous delegate? Thanks.

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  • Method overloading in groovy

    - by slojo
    I am trying to take advantage of the convenience of groovy's scripting syntax to assign properties, but having trouble with a specific case. I must be missing something simple here. I define class A, B, C as so: class A { A() { println "Constructed class A!" } } class B { B() { println "Constructed class B!" } } class C { private member C() { println "Constructed class C!" } def setMember(A a) { println "Called setMember(A)!" member = a } def setMember(B b) { println "Called setMember(B)!" member = b } } And then try the following calls in a script: c = new C() c.setMember(new A()) // works c.member = new A() // works c.setMember(new B()) // works c.member = new B() // doesn't work! The last assignment results in an error: 'Cannot cast object of class B to class A". Why doesn't it call the proper setMember method for class B like it does for class A?

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  • Print unique ascii characters in eclipse console

    - by Shaded
    Hey guys, Kind of a strange question but... here it goes. Recently my application threw an IOException that the text only had a clubs symbol in it (like the suit in cards) I know this is probably because there was a number in there that was cast to a char and printed to the screen, and I've found where that might have happened. The only problem is, I can't recreate it in eclipse because the eclipse console doesn't want to print those characters for me. All I get are boxes. I figure this is an encoding issue or something but I need eclipse to print out those characters just like the windows console would. Is there a setting I can change to do this?

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  • Serialized object in intent returning as String

    - by B_
    In my application, I am trying to pass a serializable object through an intent to another activity. The intent is not entirely created by me, it is created and passed through a search suggestion. In the content provider for the search suggestion, the object is created and placed in the SUGGEST_COLUMN_INTENT_EXTRA_DATA column of the MatrixCursor. However, when in the receiving activity I call getIntent().getSerializableExtra(SearchManager.EXTRA_DATA_KEY), the returned object is of type String and I cannot cast it into the original object class. I tried making a parcelable wrapper for my object that calls out.writeSerializable(...) and use that instead but the same thing happened. The string that is returned is like a generic Object toString(), i.e. com.foo.yak.MyAwesomeClass@4350058, so I'm assuming that toString() is being called somewhere where I have no control. Hopefully I'm just missing something simple. Thanks for the help!

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  • java.lang.classcastExcption

    - by Tara Singh
    Hi, I have an array list of objects in my application. private static ArrayList<Player> userList=new ArrayList<Player>(); In my application, I am converting this list to byte array and then sending it to other clients. At client When I am trying to cast it back to the ArrayList, its giving me casting error. I am doing this in client side after receiving this list as byte array: ArrayList<Player> pl = (ArrayList<Player>) toObject(receivedByteArray); where toObject is my function to convert the byte array to object; Any Suggestions please !!! Thanks.

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  • C - memset segfault for statically allocated char array

    - by user1327031
    I get a segfault when trying to memset an array of chars that was allocated statically, but not for an array of the same length that was allocated using malloc. variable definitions: //static char inBuff[IN_BUFF_LEN]; //dynamic char * inBuffD; function call: //static, cast used because char** != char (*) [n] serverInit(portNum, (char**) &inBuff, &serv_addr, &sockfd) //dynamic serverInit(portNum, &inBuffD, &serv_addr, &sockfd) use within the function: memset(*inBuffAdr, 0, IN_BUFF_LEN); I suspect that my problem is in the difference of the function calls, or to be more precise, my incomplete understanding of the "char** != char (*) [n]" situation. But I have been banging at this for too long and can't see the forest from the trees so any hints and advice would be very appreciated.

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  • C pointer initialization and dereferencing, what's wrong here?

    - by randombits
    This should be super simple, but I'm not sure why the compiler is complaining here. #include <stdio.h> #include <stdlib.h> int main(int argc, char *argv[]) { int *n = 5; printf ("n: %d", *n); exit(0); } Getting the following complaints: foo.c: In function ‘main’: foo.c:6: warning: initialization makes pointer from integer without a cast I just want to print the value that the pointer n references. I'm dereferencing it in the printf() statement and I get a segmentation fault. Compiling this with gcc -o foo foo.c.

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  • need help in aggregate select

    - by eugeneK
    Hi, i have a problem with selecting some values from my DB. DB is in design stages so i can redesign it a bit of needed. You can see the Diagram on this image Basically what i want to select is select c.campaignID, ct.campaignTypeName, c.campaignName, c.campaignDailyBudget, c.campaignTotalBudget, c.campaignCPC, c.date, cs.campaignStatusName ***impressions, ***clicks, ***cast(campaignTotalBudget-(clicks*campaignCPC) as decimal(18,1)) as remainingFunds from Campaigns as c left join CampaignTypes as ct on c.campaignTypeID=ct.campaignTypeID left join CampaignStatuses as cs on c.campaignStatusID=cs.campaignStatusID left join CampaignVariants as cv on c.campaignID=cv.campaignID left join CampaignVariants2Visitors as c2v on cv.campaignVariantID=c2v.campaignVariantID left join Visitors as v on c2v.visitorID=v.visitorID ..... order by c.campaignID desc Problem is that Visitors table has column named isClick so i don't know the way to separate what is impression with isClick=false and what is click isClick=true so i can show nice form with all the stuff about campaign and visitors... I don't think to split Visitors to two tables like Impressions and Click is a good idea because again i would need to have Visitors with two more tables thanks

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  • boost variant static_visitor problem picking correct function

    - by Steve
    I'm sure I'm having a problem with template resolution here, but I'm not sure why I'm having the problem. I have a static visitor I'm passing to boost variant where i've had to do template specialization for certain cases. The case for everything except for MyClass should throw in the static_visitor below. Unfortunately, when the visitor is applied to pull a MyClass out, it selects the most generic case rather than the exact match. I would type each case explicitly, but that will be rather long. So, why is the compiler resolving the most generic case over the exact match, and is there anyway to fix it template<> class CastVisitor<MyClass>:public boost::static_visitor<MyClass> { public: template<typename U> MyClass operator()(const U & i) const { throw std::exception("Unable to cast"); } MyClass operator()(const MyClass& i) { return i; } };

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  • How can I pass a type as a parameter in scala?

    - by rsan
    I'm having a really hard time trying to figure out how can I store or pass a type in scala. What I want to achive is something like this: abstract class Foo( val theType : type ) object Foo{ case object Foo1 extends Foo(String) case object Foo2 extends Foo(Long) } So at some point I can do this: theFoo match{ case String => "Is a string" case Long => "Is a long" } and when obtaining the object being able to cast it: theFoo.asInstanceOf[Foo1.theType] Is this possible? If is possible, is a good aproach? What I'm trying to achieve ultimately is writing a pseudo schema for byte stream treatment. E.g if I have an schema Array(Foo1,Foo1,Foo2,Foo3,Foo1) I could parse Arrays of bytes that complain with that schema, if at some point I have a different stream of bytes I could just write a new schema Array(Foo3, Foo4, Foo5) without having to reimplement parsing logic. Regards,

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  • In SQL how do I get the maximum value for an integer?

    - by CoffeeMonster
    Hi, I am trying to find out the maximum value for an integer (signed or unsigned) from a MySQL database. Is there a way to pull back this information from the database itself? Are there any built-in constants or functions I can use (either standard SQL or MySQL specific). At http://dev.mysql.com/doc/refman/5.0/en/numeric-types.html it lists the values - but is there a way for the database to tell me. The following gives me the MAX_BIGINT - what I'd like is the MAX_INT. SELECT CAST( 99999999999999999999999 AS SIGNED ) as max_int; # max_int | 9223372036854775807 Thanks in advance,

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  • Unusual conversion error (string to integer) asp.net

    - by Phil
    I have my repeater item template: <ItemTemplate> <tr><td><%#Container.DataItem("Category")%></td></tr> </ItemTemplate> Hooked up to: s = "SQL that works ok on server" x = New SqlCommand(s, c) x.Parameters.Add("@contentid", SqlDbType.Int) x.Parameters("@contentid").Value = contentid c.Open() r = x.ExecuteReader If r.HasRows Then Linksrepeater.DataSource = r Linksrepeater.DataBind() End If c.Close() r.Close() When I run the code I get: Invalid Cast Exception was not handled by user code (Conversion from string "category" to type 'Integer' is not valid.) I'm not sure how / why it is trying to convert "Category" to integer as in the db it is a string. Can you please tell me how to avoid this error? thanks.

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  • Passing derived objects in a constructure

    - by Clarence Klopfstein
    This is a bit of a convoluted question, hopefully I can make it clear. I am finding that this may not be possible, but am trying to see if anybody has a solution. I have four classes, two are core classes and two are those core classes extended: extUser Extends coreUser extSecurity Extends coreSecurity In the constructor for coreUser you have this: public coreUser(string id, ref coreSecurity cs) When trying to extend coreUser you would have this: public extUser(string id ref extSecurity es) : base(id, ref es) This fails because es is of type, extSecurity and the base class expects a type of coreSecurity. I've not found anyway to cast this to allow for me to override this base class in C#. In VB it works just fine. Ideas?

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