2,499 questions
0
votes
4
answers
532
views
Safe & Simple Access to Explicit Interface Members in C#
When I am working with explicit interface implementations in C#, it often becomes necessary to cast an object to one of its interfaces in order to access a member of that interface. Because of the ...
- 13.4k
12
votes
3
answers
7k
views
How do implicit conversions work in Scala?
And more specifically how does the BigInt works for convert int to BigInt?
In the source code it reads:
...
implicit def int2bigInt(i: Int): BigInt = apply(i)
...
How is this code invoked?
I can ...
- 200k
27
votes
2
answers
3k
views
Is it guaranteed that new Integer(i) == i in Java?
Consider the following snippet:
int i = 99999999;
byte b = 99;
short s = 9999;
Integer ii = Integer.valueOf(9); // should be within cache
System.out.println(new Integer(i) == i); ...
- 385k
5
votes
4
answers
4k
views
C# implicit conversions
I'm currently working on an application where I need to load data from an SQL database and then assign the retrieved values into the properties of an object. I'm doing this by using reflection since ...
- 219
1
vote
3
answers
456
views
Implicit cast from now() to a date field
I have an issue with MySQL 5.1. A datetime data type isn't implicitly casted to match a date column.
SELECT * FROM my_table WHERE my_date_field = NOW()
This request doesn't return any rows using ...
- 9,497
8
votes
1
answer
364
views
Auto-(un)boxing fail for compound assignment
Thanks to the implicit casting in compound assignments and increment/decrement operators, the following compiles:
byte b = 0;
++b; b++; --b; b--;
b += b -= b *= b /= b %= b;
b <<= b >>= b ...
- 385k
32
votes
1
answer
3k
views
Varying behavior for possible loss of precision
In Java, when you do
int b = 0;
b = b + 1.0;
You get a possible loss of precision error. But why is it that if you do
int b = 0;
b += 1.0;
There isn't any error?
- 856
3
votes
6
answers
1k
views
Using implicit conversion as a substitute for multiple inheritance in .NET
I have a situation where I would like to have objects of a certain type be able to be used as two different types. If one of the "base" types was an interface this wouldn't be an issue, but in my ...
- 16.8k
7
votes
1
answer
4k
views
Scala traits and implicit conversion confusion
The following lines work when I enter them by hand on the Scala REPL (2.7.7):
trait myTrait {
override def toString = "something"
}
implicit def myTraitToString(input: myTrait): String = input....
- 22k
2
votes
4
answers
2k
views
Implicit casting in VB.NET
The question is intended for lazy VB programmers. Please.
In vb I can do and I won't get any errors.
Example 1
Dim x As String = 5
Dim y As Integer = "5"
Dim b As Boolean = "True"
Example 2
Dim a ...
- 105k
18
votes
1
answer
2k
views
Why does Option not extend the Iterable trait directly?
Option is implicitly convertible to an Iterable - but why does it not just just implement Iterable directly:
def iterator = new Iterator[A] {
var end = !isDefined
def next() = {
val n = if (...
- 135k
11
votes
4
answers
3k
views
Explanation of casting/conversion int/double in C#
I coded some calculation stuff (I copied below a really simplifed example of what I did) like CASE2 and got bad results. Refactored the code like CASE1 and worked fine. I know there is an implicit ...
- 7,065
2
votes
1
answer
340
views
Question about implicit operator overloading in c#
MyClass c = 10;
Is there any way to make this code work? I know that through the implicit operator overloading you can get the opposite to work:
int i = instanceOfMyClass;
Thanks
- 106k
5
votes
1
answer
1k
views
Why does this implicit type conversion in C# fail?
Background:
Let's assume I've got the following class:
class Wrapped<T> : IDisposable
{
public Wrapped(T obj) { /* ... */ }
public static implicit operator Wrapped<T>(T obj)
...
1
vote
1
answer
165
views
How do i cast A to object to class A when B can typcast to A?
Basically i want to do this. aa causes a bad cast exception.
NOTE: o can be ANYTHING. It may not be B, it can be C, D, E, F etc. But this should work as long as o is a class that can typecast into A (...
user34537
-5
votes
3
answers
286
views
How do I use implicit and explicit casts? [duplicate]
Possible Duplicate:
Identify the implicit cast and explicit cast
int a = 2, b = 3;
float f = 2.5;
double d = -1.2;
int int_result;
float real_result;
real_result = a * f;
real_result = (float) a ...
- 45
3
votes
4
answers
6k
views
Implicit casting Integer calculation to float in C++
Is there any compiler that has a directive or a parameter to cast integer calculation to float implicitly. For example:
float f = (1/3)*5;
cout << f;
the "f" is "0", because calculation's ...
- 33
2
votes
2
answers
1k
views
C++, how implicit conversion/constructor are determined?
How does C++ determine implicit conversion/construction of objects few levels deep?
for example:
struct A {};
struct B: A {};
struct C { operator B() { return B(); } };
void f(A a) {}
int main(void)...
- 51.8k
0
votes
4
answers
2k
views
Why friend overloaded operator is preferred to conversion operator in this case
Hi I have a code like this, I think both the friend overloaded operator and conversion operator have the similar function. However, why does the friend overloaded operator is called in this case? What'...
- 26k
3
votes
1
answer
933
views
scala 2.8 implict java collections conversions
I have problem with JavaConversions with 2.8 beta:
import scala.collection.JavaConversions._
class Utils(dbFile : File, sep: String) extends IUtils {
(...)
def getFeatures() : java.util.List[...
- 153
2
votes
4
answers
485
views
why does a char + another char = a weird number
Here's the code snippet:
public static void main (String[]arg)
{
char ca = 'a' ;
char cb = 'b' ;
System.out.println (ca + cb) ;
}
The output is:
195
Why is this the case? I would ...
- 15k
27
votes
5
answers
8k
views
How to tell if Type A is implicitly convertible to Type B
Given Type a and Type b, how can I, at runtime, determine whether there's an implicit conversion from a to b?
If that doesn't make sense, consider the following method:
public PropertyInfo ...
- 60.2k
61
votes
3
answers
6k
views
Conditional operator cannot cast implicitly?
I'm a little stumped by this little C# quirk:
Given variables:
Boolean aBoolValue;
Byte aByteValue;
The following compiles:
if (aBoolValue)
aByteValue = 1;
else
aByteValue = 0;
But this ...
- 16.8k
0
votes
2
answers
259
views
Implicit Conversion
My program was:-
#include < iostream.h>
#include < conio.h>
struct base
{
protected:
void get()
{
cin>>a>>b;
}
public:
base(int i=0, int j=0);
...
user260084
1
vote
5
answers
1k
views
Stopping an implicit cast on operator delete
My String class provides an operator char* overload to allow you to pass the string to C functions.
Unfortunately a colleague of mine just inadvertently discovered a bug.
He effectively had the ...
- 62.5k
8
votes
2
answers
832
views
Using string constants in implicit conversion
Consider the following code:
public class TextType {
public TextType(String text) {
underlyingString = text;
}
public static implicit operator String(TextType text) {
...
- 9,622
13
votes
3
answers
5k
views
Is there a way to do dynamic implicit type casting in C#?
Given this class with an implicit cast operator:
public class MyDateTime
{
public static implicit operator MyDateTime(System.Int64 encoded)
{
return new MyDateTime(encoded);
}
...
- 2,069
7
votes
2
answers
2k
views
Implicit version of IsAssignableFrom?
In my code using reflections i wrote
if (f.FieldType.IsAssignableFrom("".GetType()))
I have a class that has an implicit conversion to strings. However the if statement above doesnt catch it. How can ...
user34537
5
votes
1
answer
2k
views
Problem with implicit conversion and null
I have this function
public static implicit operator MyClass(string v) { return new MyClass(v); }
and write var.myclass = null;. This calls the implicit operator and passes null as string, which ...
user34537
3
votes
1
answer
2k
views
Invaid cast exception, even when I have an implicit cast operator defined (in asp mvc app)
I have an mvc model class created and one of the properties is of type 'MyObject'. It also has a System.ComponentModel.DataAnnotations.StringLength attribute on it.
MyObject as implicit cast ...
- 46.8k
3
votes
2
answers
1k
views
C++ templates and ambiguity problem
I have a subset of a pointer class that look like:
template <typename T>
struct Pointer
{
Pointer();
Pointer(T *const x);
Pointer(const Pointer &x);
template <...
- 4,609
1
vote
4
answers
1k
views
simulate C++ function template instantiation with implicit conversion
I already asked two questions related to what I'm trying to do (one resolved, one of which I will close soon). I know that C++ template instantiation does not allow any implicit conversions (see for ...
- 3,663
1
vote
1
answer
570
views
System.Type; implicit cast to string
While looking at the System.Type class under the Code Definition Window, I cannot seem to understand how an instance of this class is implicitly cast to string. For example, on the following code:
...
- 3,251
5
votes
3
answers
2k
views
No implicit int -> short conversion in ternary statement
short s;
s = (EitherTrueOrFalse()) ? 0 : 1;
This fails with:
error CS0266: Cannot implicitly
convert type 'int' to 'short'. An
explicit conversion exists (are you
missing a cast?)
Can anyone ...
- 641
4
votes
4
answers
2k
views
Will the c# compiler perform multiple implicit conversions to get from one type to another?
Let's say you have yourself a class like the following:
public sealed class StringToInt {
private string _myString;
private StringToInt(string value)
{
_myString = value;
...
- 39.7k
8
votes
5
answers
12k
views
C++ operator overloading and implicit conversion
I have a class that encapsulates some arithmetic, let's say fixed point calculations. I like the idea of overloading arithmetic operators, so I write the following:
class CFixed
{
CFixed( int );
...
- 2,551
2
votes
3
answers
7k
views
Which Json deserializer renders IList<T> collections?
I'm trying to deserialize json to an object model where the collections are represented as IList<T> types.
The actual deserializing is here:
JavaScriptSerializer serializer = new ...
- 11.6k
2
votes
1
answer
1k
views
Runtime InvalidCastException with implicit cast operator
I have a C# library that internal clients configure with VB.Net
Their scripts are throwing an InvalidCastException where they really shouldn't.
So the code is something like this (massively ...
- 157k
11
votes
6
answers
8k
views
Getting rid of error C2243
Is it possible to getting rid of error C2243?
class B {};
class D : protected B {};
D d;
B *p = &d; // conversion from 'D *' to 'B &' exists, but is inaccessible
I had this error in my app ...
- 2,449
5
votes
10
answers
5k
views
Why is implicit conversion allowed from superclass to subclass?
Can someone tell me why the line with "//Compiles" compiles, and why the line with "//Doesn't Compile" does not?
I don't understand why A would be implicitly convertible to B, not the other way ...
HC
9
votes
9
answers
11k
views
C++ rely on implicit conversion to bool in conditions?
I found the following rule in a coding standards sheet :
Do not rely on implicit conversion to bool in conditions.
if (ptr) // wrong
if (ptr != NULL) // ok
How reasonable/usefull is this ...
- 5,384
1
vote
2
answers
660
views
JavaScript implicit conversions in equality with a string
How does JavaScript behave for the comparisons true == "true" and (0 == "0")?
- 5,753
6
votes
4
answers
2k
views
Why do implicit conversion member functions overloading work by return type, while it is not allowed for normal functions?
C++ does not allow polymorphism for methods based on their return type. However, when overloading an implicit conversion member function this seems possible.
Does anyone know why? I thought operators ...
- 2,045
30
votes
4
answers
7k
views
What is the difference between double a = a + int b and int a += double b?
Why does:
public class Addition {
public static void main() {
int a = 0;
double b = 1.0;
a = a + b;
System.out.println(a);
}
}
not compile but:
public class Addition {
...
- 375
23
votes
5
answers
11k
views
implicit operator
I just saw it was using in one of the recent answers:
public static implicit operator bool(Savepoint sp)
{
return sp != null;
}
Why do we need word implicit here, and what does it mean?
Sasha
3
votes
5
answers
2k
views
Unable to find operator via implicit conversion in C++
When writing a class to act as a wrapper around a heap-allocated object, I encountered a problem with implicit type conversion that can be reduced to this simple example.
In the code below the ...
- 273
156
votes
16
answers
98k
views
Can we define implicit conversions of enums in c#?
Is it possible to define an implicit conversion of enums in c#?
something that could achieve this?
public enum MyEnum
{
one = 1, two = 2
}
MyEnum number = MyEnum.one;
long i = number;
If not, ...
- 6,370
64
votes
8
answers
27k
views
Can you use keyword explicit to prevent automatic conversion of method parameters?
I know you can use C++ keyword 'explicit' for constructors of classes to prevent an automatic conversion of type. Can you use this same command to prevent the conversion of parameters for a class ...
- 3,643
71
votes
1
answer
39k
views
implicit operator using interfaces
I have a generic class that I'm trying to implement implicit type casting for. While it mostly works, it won't work for interface casting. Upon further investigation, I found that there is a ...
- 28.5k