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How does std::move() transfer values into RValues?
...reference<T>::type&& move(T&& arg)
{
return static_cast<typename remove_reference<T>::type&&>(arg);
}
Let's start with the easier part - that is, when the function is called with rvalue:
Object a = std::move(Object());
// Object() is temporary, which ...
Cast an instance of a class to a @protocol in Objective-C
... [vc protocolMethod];
}
The UIViewController <MyProtocol> * type-cast translates to "vc is a UIViewController object that conforms to MyProtocol", whereas using id <MyProtocol> translates to "vc is an object of an unknown class that conforms to MyProtocol".
This way the compiler wil...
Converting bool to text in C++
...Boost that can help us out here. Boost has a nice function called lexical_cast. We can use it thus:
boost::lexical_cast<std::string>(my_bool)
Now, it's true to say that this is higher overhead than some macro; stringstreams deal with locales which you might not care about, and create a dy...
Does the 'mutable' keyword have any purpose other than allowing the variable to be modified by a con
....
Without the mutable keyword you will eventually be forced to use const_cast to handle the various useful special cases it allows (caching, ref counting, debug data, etc.). Unfortunately const_cast is significantly more destructive than mutable because it forces the API client to destroy the cons...
What is an “unwrapped value” in Swift?
...gift:getGift())
//Now we have to unwrap f00, unwrap its entry, then force cast it into the type we hope it is, and then repeat this in nested fashion until we get to the final value.
var b4r = (((((((((((f00![10]! as! [Int:Any?])[9]! as! [Int:Any?])[8]! as! [Int:Any?])[7]! as! [Int:Any?])[6]! as! ...
What are the main purposes of using std::forward and which problems it solves?
... modify these
The third attempt accepts const-references, but then const_cast's the const away:
template <typename A, typename B, typename C>
void f(const A& a, const B& b, const C& c)
{
E(const_cast<A&>(a), const_cast<B&>(b), const_cast<C&>(c))...
How to cast/convert pointer to reference in C++
...
Call it like this:
foo(*ob);
Note that there is no casting going on here, as suggested in your question title. All we have done is de-referenced the pointer to the object which we then pass to the function.
...
How can I cast int to enum?
How can an int be cast to an enum in C#?
31 Answers
31
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What happens if you static_cast invalid value to enum class?
...
Answering with a quote from the C++11 and C++14 Standards:
[expr.static.cast]/10
A value of integral or enumeration type can be explicitly converted to an enumeration type. The value is unchanged if the original value is within the range of the enumeration values (7.2). Otherwise, the resulti...
What does = +_ mean in JavaScript
...
r = +_;
+ tries to cast whatever _ is to a number.
_ is only a variable name (not an operator), it could be a, foo etc.
Example:
+"1"
cast "1" to pure number 1.
var _ = "1";
var r = +_;
r is now 1, not "1".
Moreover, according to the M...