大约有 30,000 项符合查询结果（耗时：0.0531秒） [XML]
What's the yield keyword in JavaScript?
...MO.
The function containing the yield keyword is a generator. When you call it, its formal parameters are bound to actual arguments, but its body isn't actually evaluated. Instead, a generator-iterator is returned. Each call to the generator-iterator's next() method performs another pass through...
PDO mysql: How to know if insert was successful
... be thrown in case of a database error, and it will bubble up to the site-wide error handler that eventually will result in a common 500 error page.
To handle the expected error, like a duplicate primary key, and if you have a certain scenario to handle this particular error, then use a try..catch o...
How to call getClass() from a static method in Java?
... that must have some static methods. Inside these static methods I need to call the method getClass() to make the following call:
...
Does Typescript support the ?. operator? (And, what's it called?)
...
Update: it is supported as of TypeScript 3.7 and called Optional chaining: https://www.typescriptlang.org/docs/handbook/release-notes/typescript-3-7.html#optional-chaining
I can't find any reference to it whatsoever in the TypeScript language specification.
As far as what...
Why would adding a method add an ambiguous call, if it wouldn't be involved in the ambiguity
...ong is completely unsurprising; the "ambiguous method" error heuristic basically picks any two methods from the candidate set if a best method cannot be determined. It is not very good at finding the "real" ambiguity, if in fact there is one.
One might reasonably ask why that is. It is quite tricky...
Static variable inside of a function in C
...oo() to the return from foo(); so it would be re-initialized to 5 on every call.
The keyword static acts to extend the lifetime of a variable to the lifetime of the programme; e.g. initialization occurs once and once only and then the variable retains its value - whatever it has come to be - over a...
In Windows Azure: What are web role, worker role and VM role?
...anually enable it)
VM roles are Windows Server 2008 images you construct locally via Hyper-V and upload to Azure (and are now discontinued and no longer available as of May 31, 2013
Virtual Machines are Windows or Linux images created in Azure, stored as a vhd in your own storage, and have several e...
What is stack unwinding?
...the scope is of the function func.) This is done by the compiler inserting calls to destructors of automatic (stack) variables.
Now this is a very powerful concept leading to the technique called RAII, that is Resource Acquisition Is Initialization, that helps us manage resources like memory, datab...
How do I add a class to a given element?
... of your new class to the className property of the element. First, put an id on the element so you can easily get a reference.
<div id="div1" class="someclass">
<img ... id="image1" name="image1" />
</div>
Then
var d = document.getElementById("div1");
d.className += " oth...
what is the basic difference between stack and queue?
...t is the first one to come out. This is LIFO. Adding a piece of paper is called "pushing", and removing a piece of paper is called "popping".
Imagine a queue at the store. The first person in line is the first person to get out of line. This is FIFO. A person getting into line is "enqueued",...