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Questions tagged [implicit-conversion]

Converting an object, variable or value from one type to another to satisfy a type restriction, without specifically requesting that conversion through language syntax.

Converting an object, variable or value from one type to another to satisfy a type restriction, without specifically requesting that conversion through language syntax.

Implicit conversion is a subset of .

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Double pointer const-correctness warnings in C

A pointer to non-const data can be implicitly converted to a pointer to const data of the same type: int *x = NULL; int const *y = x; Adding additional const qualifiers to match the additional indirection should logically work the same…
Michael Koval
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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 compiler error: "User-defined conversion from interface"…
Michael Meadows
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mysql datetime comparison

For example the following query works fine: SELECT * FROM quotes WHERE expires_at <= '2010-10-15 10:00:00'; But this is obviously performing a 'string' comparison - I was wondering if there was a function built in to MySQL that specifically…
MAX POWER
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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 will not: aByteValue = aBoolValue ? 1 : 0; Error…
MPelletier
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Serious bugs with lifted/nullable conversions from int, allowing conversion from decimal

I think this question will bring me instant fame here on Stack Overflow. Suppose you have the following type: // represents a decimal number with at most two decimal places after the period struct NumberFixedPoint2 { decimal number; // an…
Jeppe Stig Nielsen
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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 method? I have two class members, one which takes a…
Superpolock
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Should implicit classes always extend AnyVal?

Say I'm writing an extension method implicit class EnhancedFoo(foo: Foo) { def bar() { /* ... */ } } Should you always include extends AnyVal in the class defininition? Under what circumstances would you not want to make an implicit class a value…
Luigi Plinge
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Why does a generic type constraint result in a no implicit reference conversion error?

I have created a couple of interfaces and generic classes for working with agenda appointments: interface IAppointment where T : IAppointmentProperties { T Properties { get; set; } } interface IAppointmentEntry where T :…
Rens
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Concatenate two Dictionaries

Given some Dictionaries Dictionary GroupNames = new Dictionary(); Dictionary AddedGroupNames = new Dictionary(); I am unable to merge them into one: GroupNames =…
Alexander
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Ternary operator implicit cast to base class

Consider this piece of code: struct Base { int x; }; struct Bar : Base { int y; }; struct Foo : Base { int z; }; Bar* bar = new Bar; Foo* foo = new Foo; Base* returnBase() { Base* obj = !bar ? foo : bar; return obj; } int…
Hatted Rooster
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Why does an implicit conversion operator from to accept ?

This is a weird behaviour that I cannot make sense of. In my example I have a class Sample and an implicit conversion operator from T to Sample. private class Sample { public readonly T Value; public Sample(T value) { Value…
Noel Widmer
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Nonintuitive result of the assignment of a double precision number to an int variable in C

Could someone give me an explanation why I get two different numbers, resp. 14 and 15, as an output from the following code? #include int main() { double Vmax = 2.9; double Vmin = 1.4; double step = 0.1; double a…
GeorgiD
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When does lvalue-to-rvalue conversion happen, how does it work, and can it fail?

I see the term "lvalue-to-rvalue conversion" used in many places throughout the C++ standard. This kind of conversion is often done implicitly, as far as I can tell. One unexpected (to me) feature of the phrasing from the standard is that they…
orm
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Why is signed and unsigned addition converted differently for 16 and 32 bit integers?

It seems the GCC and Clang interpret addition between a signed and unsigned integers differently, depending on their size. Why is this, and is the conversion consistent on all compilers and platforms? Take this example: #include #include…
Nikolaj
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Passing int as bool argument in C++

could someone explain what happens in this code: example here: https://ideone.com/1cFb4N #include using namespace std; class toto { public: bool b; toto(bool x) { cout<< "constructor bool:" << (x ? "true":…
serge
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