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Search found 763 results on 31 pages for 'casting'.

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• Call virtual method from base class on object of derived type

  - by Nikola Smiljanic

  class Base { public: virtual void foo() const { std::cout << "Base"; } }; class Derived : public Base { public: virtual void foo() const { std::cout << "Derived"; } }; Derived d; // call Base::foo on this object Tried casting and function pointers but I couldn't do it. Is it possible to defeat virtual mechanism (only wondering if it's possible)?

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• Will the "generified" version of JTree (TreeModel, TreeNode, ...) be in JDK7?

  - by java.is.for.desktop

  I found out recently that JList (finally!) was "generified" in JDK7. Why JTree and related classes/interfaces are not changed the same? It would be a huge improvement. Casting Object is going on one's nerves.

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• NAN mixing float and GLFloat?

  - by carrots

  This often returns NAN ("Not A Number") depending on input: #define PI 3.1415f GLfloat sineEaseIn(GLfloat ratio) { return 1.0f-cosf(ratio * (PI / 2.0f)); } I tried making PI a few digits smaller to see if that would help. No dice. Then I thought it might be a datatype mismatch, but float and glfloat seem to be equivalent: gl.h typedef float GLfloat; math.h extern float cosf( float ); Is this a casting issue?

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• What makes the availability of both primitive and object-wrapped values in JavaScript useful?

  - by Delan Azabani

  I wrote a blog post a while ago detailing how the availability of both primitive and object-wrapped value types in JavaScript (for things such as Number, String and Boolean) causes trouble, including but not limited to type-casting to a boolean (e.g. object-wrapped NaN, "" and false actually type-cast to true). My question is, with all this confusion and problems, is there any benefit to JavaScript having both types of values for the built-in classes?

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• Shallow copying a list with downcasting

  - by Mohit

  I have the class herichary as follows CEntity----CNode---CElement I have a class Nodes : List<Cnode> and Class Elements : List<Element> Node class contain common item common across different project Element class has item specific to a project. I have to shallow copy the element list into the node list (basically down casting the elements to nodes)

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• Is it possible in .NET 3.5 to specify an enum type?

  - by RoboShop

  I have a enumerator which map to a bunch of int example enum MyEnum { Open = 1, Closed = 2, Exit = 4 } I find though that when I want to assign this to an integer, I have to cast it first. int myEnumNumber = **(int)** MyEnum.Open; Is it possible to specify the type of an enum so that it is implicit that there is a integer assigned to any value within the enum? That way, I do not need to keep casting it to an int if I want to use it thanks

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• Convert Subclass to Inherited Class

  - by Dave

  I have a C# .NET 2.0 project A that has a form (TreeForm) that uses Tree objects. I have a project B that has a class Oak that inherits Tree. When I try to reference and use the TreeForm in project B with my Oak objects, it's looking for objects of type Tree. I've tried casting the Oak objects to Tree, but I get the error "Cannot convert type Oak to Tree". How can I use my Oak objects in the TreeForm from project A?

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• Why does Int32.MaxValue * Int32.MaxValue == 1 ???

  - by Greg Balajewicz

  OK, I know, Int32.MaxValue * Int32.MaxValue will yield a number larger than Int32 BUT, shouldn't this statement raise some kind of an exception? I ran across this when doing something like IF (X * Y Z) where all are Int32. in X and Y are sufficiently large enough, you get a bogus value from X*Y Why is this so and how to get around this? besides casting everything to int64

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• Preserving the dimensions of a slice from a Numpy 3d array

  - by Brendan

  I have a 3d array, a, of shape say a.shape = (10, 10, 10) When slicing, the dimensions are squeezed automatically i.e. a[:,:,5].shape = (10, 10) I'd like to preserve the number of dimensions but also ensure that the dimension that was squeezed is the one that shows 1 i.e. a[:,:,5].shape = (10, 10, 1) I have thought of re-casting the array and passing ndmin but that just adds the extra dimensions to the start of the shape tuple regardless of where the slice came from in the array a.

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• Why does this code sometimes return NaN?

  - by carrots

  This often returns NAN ("Not A Number") depending on input: #define PI 3.1415f GLfloat sineEaseIn(GLfloat ratio) { return 1.0f-cosf(ratio * (PI / 2.0f)); } I tried making PI a few digits smaller to see if that would help. No dice. Then I thought it might be a datatype mismatch, but float and glfloat seem to be equivalent: gl.h typedef float GLfloat; math.h extern float cosf( float ); Is this a casting issue?

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• wanna store Object in MySQL database

  - by kandarp

  I have a variable in java which return type is Object(java.lang.Object). I want to store this variable value in MySQL database without casting in any other primitive data type. Is there any data type available in MySQL related to Object? If anybody knows, please reply at your earliest time. Thanks,

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• Warning: pointer of type 'void *' used in subtraction

  - by idealistikz

  Although it runs correctly, the following results in the aforementioned compiler warning: return ((item - (my->items))/(my->itemSize)); 'item' is a 'void *'; 'my-items' is a 'void *'; 'my-itemSize' is an 'int' Casting 'item' and 'my-items' as an 'int *' caused the program to run improperly. What is the best way to remove the warning?

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• What's the best way to draw a fullscreen quad in OpenGL 3.2?

  - by Phineas

  I'm doing ray casting in the fragment shader. I can think of a couple ways to draw a fullscreen quad for this purpose. Either draw a quad in clip space with the projection matrix set to the identity matrix, or use the geometry shader to turn a point into a triangle strip. The former uses immediate mode, deprecated in OpenGL 3.2. The latter I use out of novelty, but it still uses immediate mode to draw a point.

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• Types questions in ANSI C

  - by shaharg

  Hi, I having few questions about typed in ANSI C: 1. what's the difference between "\x" in the beginning of a char to 0x in the beginning of char (or in any other case for this matter). AFAIK, they both means that this is hexadecimal.. so what's the difference. when casting char to (unsigned), not (unsigned char) - what does it mean? why (unsigned)'\xFF' != 0xFF? Thanks!

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• Difference between DirectCast() and CType() in VB.Net

  - by Chapso

  I am an experienced C/C++/C# programmer who has just gotten into VB.NET. I generally use CType (and CInt, CBool, CStr) for casts because it is less characters and was the first way of casting which I was exposed to, but I am aware of DirectCast and TryCast as well. Simply, are there any differences (effect of cast, performance, etc.) between DirectCast and CType? I understand the idea of TryCast.

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• In C# why can't a conditional operator implicitly cast to a nullable type

  - by Tim Jarvis

  I am curious as to why an implicit cast fails in... int? someValue = SomeCondition ? ResultOfSomeCalc() : null; and why I have to perform an explicit cast instead int? someValue = SomeCondition ? ResultofSomeCalc() : (int?)null; It seems to me that the compiler has all the information it need to make an implicit casting decision, no?

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• Interesting task using random numbers only

  - by psihodelia

  Given any number of the random real numbers from the interval [0,1] is there exist any method to construct a floating point number with zero decimal part? Your algorithm can use only random() function calls and no variables or constants. No constants and variables are allowed, no type casting is allowed. You can use for/while, if/else or any other programming language operands.

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• C: performance of assignments, binary operations, et cetera...

  - by Shinka

  I've heard many things about performance in C; casting is slow compared to normal assignments, functional call is slow, binary operation are much faster than normal operations, et cetera... I'm sure some of those things are specific to the architecture, and compiler optimization might make a huge difference, but I would like to see a chart to get a general idea what I should do and what I should avoid to write high-performance programs. Is there such a chart (or a website, a book, anything) ?

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• Invisible class from WebService in application

  - by phenevo

  I've got webservice which has multiple classess My winforms application see theirs, but not everyone. This application has webreference to this webservice. I think that this application see every class which is used in WebMethod, but I using parent class in WebMethod and I wanna casting it to another class,which is not used at webmethod.

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• What is the <T> in Cast<T>() or List<T> in C#

  - by Jeremy

  I know this is probably a dupe, but I can't for the life of me remember what the name is or even how to look it up. I know T would the the Type you are casting to, but what is the technical name of it.

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• (gcc) Multi-Dim Array or Double Pointer for Warning-free Compile

  - by paul simmons

  Hi, I have a function, which is called sometimes with regular, sometimes dynamic arrays. If I define the function as function_name(int[10][10] a) and send int** as a parameter, I get a warning. Opposite, if I declare function_name(int** a) and send int[][] as a parameter (after casting) I cannot access to array elements inside function. What is the correctest way?

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• Get a char from a CString

  - by Sunscreen

  I have created a function that has as input a char szMyChar; (using it in a switch statement). Now I have a CString havong just a char, lets say CString strString = "A"; An option to call the function could be: if (strString == "A") CallMyFunc('A'); though it is clumsy. I tried atoi (returns 0) and casting though neither works. Any ideas? Thanks, Sun

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• Why is "int + string" possible in statically-typed C# but not in dynamically-typed Python?

  - by Salvador Dali

  While studying C# I found it really strange, that dynamically typed Python will rise an error in the following code: i = 5 print i + " " whereas statically typed C# will normally proceed the similar code: int i = 5; Console.Write(i + " "); I would expect other way around (in python I would be able to do this without any casting, but C# would require me to cast int to string or string to int). Just to highlight, I am not asking what language is better, I am curious what was the reason behind implementing the language this way.

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• Url routing asp.net 4

  - by user510336

  Hello all , I am trying to create url routing like this http://msdn.microsoft.com/en-us/magazine/dd347546.aspx but I am having few questions , first why he is adding lines to the web.config , I tested it and it didnt appear that they're doing something as I commented them and nothing major appeared second I am having this line of code that is crashing var display = BuildManager.CreateInstanceFromVirtualPath(_virtualPath,typeof(Page)) as IProfileHandler; when casted as ihttphandler it's working , but when I am casting it to iprofilehandler(which is implemeting ihttphandler) it's giving null !

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• PL/SQL 'select in' from a list of values whose type are different from the outer query

  - by Attilah

  I have the following tables : Table1 ( Col1 : varchar2, Col2 : number, Col3 : number) Table2 ( Col1 : number, Col2 : varchar2, Col3 : varchar2) I want to run a query like this : select distinct Col2 from Table1 where Col1 in ( select Col1 from Table2 ) Table1.Col1 is of type varchar2 while Table2.Col1 is of type number. so, I need to do some casting, it seems but it fails to succeed. The problem is that any attempts to run the query returns the following error : ORA-01722: invalid number 01722. 00000 - "invalid number" *Cause: *Action: Table1.Col1 contains some null values.

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