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C++ equivalent of java's instanceof
...
Try using:
if(NewType* v = dynamic_cast<NewType*>(old)) {
// old was safely casted to NewType
v->doSomething();
}
This requires your compiler to have rtti support enabled.
EDIT:
I've had some good comments on this answer!
Every time you need...
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 ...
Linux下部署企业级邮件服务器(postfix + dovecot + extmail) - 开源 & Gith...
Linux下部署企业级邮件服务器(postfix + dovecot + extmail)postfix + dovecot + extmail解决方案搭建邮件服务器全攻略，以及搭建过程中常见问题的解决方法汇总。首先通过一幅图看看整个解决方案的原理：
当用户通过extmail登陆时，首先extm...
Enum String Name from Value
...
You can convert the int back to an enumeration member with a simple cast, and then call ToString():
int value = GetValueFromDb();
var enumDisplayStatus = (EnumDisplayStatus)value;
string stringValue = enumDisplayStatus.ToString();
...
Ignore Typescript Errors “property does not exist on value of type”
...erHtmlElement.getBBox();
###Edit, late 2016
Since TypeScript 1.6 prefered casting operator is as those lines can be squashed into:
let coordinates = (outerElement[0] as any).getBBox();
###Other solutions
Of course if you'd like to do it right, which is an overkill sometimes, you can:
Create own i...
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! ...
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...
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...
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 loop through all enum values in C#? [duplicate]
...Foos));
Or the typed version:
var values = Enum.GetValues(typeof(Foos)).Cast<Foos>();
I long ago added a helper function to my private library for just such an occasion:
public static class EnumUtil {
public static IEnumerable<T> GetValues<T>() {
return Enum.GetVa...