I have this simple structure: 1 parent, and two different childs. public class Parent{} public class ChildA : Parent{} public class ChildB : Parent{} I have an object objA of type ChildA, which I want to cast to ChildB. My naive approach says: ChildA objA = new ChildA(); ChildB objB = (ChildB)objA; But this is not directly possi...
Extends. I thought I was being cool when I did something like: bool hasParent() { return this->parentNode ; } Even with a (bool) cast, the warning still doesn't go away. Where this->parentNode is NULL when there is no parent node. But I'm getting: warning C4800: 'Node *' : forcing value to bool 'true' or 'false' (performance w...
I would like to correctly cast a value in a grid to an integer. The problem is that the value in the grid can sometimes be equal to an empty string which will cause a cast error. Is there a sophisticated way to try the cast without erroring on non-numeric values, or should I just do check beforehand? The cast code below is the code which...
I need to implement a function which returns a TDictionary, without specifying the exact types. The returned value could be a TDictionary<string,Integer>, TDictionary<string,string> or TDictionary<string,Boolean> Could I declare the function with TDictionary as result parameter: function GetMap: TDictionary; and then cast the return ...
What doesn't this work: (int)08 == (int)09==0 But this and this does? (int)07==7 (int)06==6 ...
public class UserLoginInfo { public UserRole Role; public string Username; public static UserLoginInfo FetchUser(string username, string password) { using (var connection = Utils.Database.GetConnection()) using (var command = new SqlCommand("SELECT [Username], [Password], [Role] FROM [Users] WHERE [Userna...
I am using signed to unsigned byte(int8_t) cast to pack byts. uint32_t(uint8_t(byte)) << n This works using GCC on Intel Linux. Is that portable for other platforms/compilers, for example PowerPC? is there a better way to do it? using bitset is not possible in my case. I am using stdint via boost ...
Hi, I'm reading a book and I found that reinterpret_cast should not be used directly, but rather casting to void* in combination with static_cast: T1 * p1=... void *pv=p1; T2 * p2= static_cast<T2*>(pv); instead of: T1 * p1=... T2 * p2= reinterpret_cast<T2*>(p1); However, I can't find an explanation why is this better than the dire...
perhaps it's a very stupid question but I'm having a hard time figuring this out =) in C or C++ it is said that the maximum number a size_t (an unsigned int data type) can hold is the same as casting -1 to that data type. for example see http://stackoverflow.com/questions/1420982/invalid-value-for-sizet Why?? I'm confused.. I mean, (t...
I have the code of a simple game, where an AgentInterface must be implemented in order to create an agent controller for one of the characters in the game. GameState is a class the implements GameStateInterface, and an object that implements this interface can be passed to the agent, so the agent can read and analyze the data from game s...
I was poking around PHPs casting mechanism, and ran into an odd case when casting an array as an object $o = (object) array('1'=>'/foo/bar'); $o = new stdClass(); var_dump($o); As I understand it, PHP properties need to be declared with the same rules as PHP variables. That is A valid variable name starts with a letter or underscore...
Q1. Why does using NULL pointers with static_cast cause crashes while dynamic_cast and reinterpret_cast give a NULL pointer in return? The problem occurred in a method similar to the one given below: void A::SetEntity(B* pEntity, int iMyEntityType) { switch (iMyEntityType) { case ENTITY1: { Set1(static_cast<C...
What is the correct way of casting (in C++/CLI) from a native code enum to a managed code enum which contain the same enum values? Is there any difference with using the C# way of casting like for example (int) in C++/CLI. ...
The next code works fine in C#: Int32 a, b; Int16 c; a = 0x7FFFFFFF; b = a & 0xFFFF; c = (Int16)b; But this code crash with a OverflowException in VB.Net. Dim a, b As Int32 Dim c As Int16 a = &H7FFFFFFF b = a And &HFFFF c = CType(b, Int16) Both codes seems the same to me. What is the differ...
Hello, I have tried to use this code in VS2008 (and may have included too much context in the sample...): class Base { public: void Prepare() { Init(); CreateSelectStatement(); // then open a recordset } void GetNext() { /* retrieve next record */ } private: virtual void Init() = 0; virtu...
Is there built in version of the type casting functions that preserves units and if not how would I make them? So for example with this code how would I cast intWithSecondsMeasure to a float without losing the measure or multiplying by 1.0<s>? [<Measure>] type s let intWithSecondsMeasure = 1<s> let justAFloat = float intWithSecondsMeasu...
C#: static int F(object x) { return x is string ? 1 : 2; } Haskell? The tricky bit seems to me that Haskell does not have a root type object. Edited: I do not care about converting to string. I want to know how to typecast (for example to see if an object is a Customer or an Order. ...
Trying to learn some f# and I've run into a couple of hangups. Here's the code: #light module HtmlModule type HtmlString(text:string) = override x.ToString() = text type HtmlAttribute(key:string, value:string) = inherit HtmlString(key + "=\"" + value + "\""); type HtmlElement(tag: string, ?contents:list<'a> when 'a :> HtmlSt...
Sometimes I have to implement an interface or inherit a virtual (MustInherit) that the base method expects an object, whilst I know that the value I will be passing will always be an Integer for example. What should be the best performance from the examples below: Public Sub DoSomething(ByVal obj As Object) 'option 1: Dim x As ...
Hi! use in a project two libraries. Irrlicht and OpenMesh. Both libraries feature a Vector3 format. Irrlicht has vector3df which stores three floats and OpenMesh has VectorT OpenMesh has got some functions which return a VectorT - i know that N is 3 and the scalar is of type float. How can I make the types compatible such that i can c...