大约有 45,000 项符合查询结果（耗时：0.0511秒） [XML]
When and why would you seal a class?
...to cast a non-sealed class to any random interface, compiler doesn't throw error; but when sealed is used the compiler throws error that it can't convert. Sealed class brings additional code access security.
https://www.codeproject.com/Articles/239939/Csharp-Tweaks-Why-to-use-the-sealed-keyword-on-c...
Can a class member function template be virtual?
... like this:
X x;
x.func2<string>("X x");
g++ report the following error:
vtempl.cpp:34: error: invalid use of `virtual' in template declaration of `virtu
al void X::func2(const T&)'
So it is obvious that:
virtual member function can be used in a class template. It is easy for compi...
What are the disadvantages of using persistent connection in PDO
... happened seemingly at random. It turned out that those once-a-week fatal errors that our users diligently squeezed out of our app were leaving locked tables, abandoned transactions and other unfortunate wonky states.
This sob-story has a point: It broke things that we never expected to break, all...
How do HTML parses work if they're not using regexp?
... The primary problem with HTML parsers is that upon encountering an error, you're not okay to spit out "Parse error" and leave it at that. You enter quirks mode and try to make out the best you can from the mess you encountered, including mismatched tags, [{]} style interlace, and all kinds o...
How to use Git Revert
...t is still confusing people (like me)
As a beginner, after some trial and error (more errors than trials) I've got an important point:
git revert requires the id of the commit you want to remove keeping it into your history
git reset requires the commit you want to keep, and will consequentially...
Why must we define both == and != in C#?
...our compiled the code in the example program, you will see it runs with no errors. However, if you tried adding the line:
cout << (a != b);
you will get
compiler error C2678 (MSVC) : binary '!=' : no operator found which takes a left-hand operand of type 'Test' (or there is no acceptab...
In which case do you use the JPA @JoinTable annotation?
... recent versions of Hibernate refuse to start up by printing the following error:
org.hibernate.AnnotationException:
Associations marked as mappedBy must not define database mappings
like @JoinTable or @JoinColumn
Let's pretend that you have an entity named Project and another entity na...
When does invoking a member function on a null instance result in undefined behavior?
...mplies. The rationale says that it should be allowed because "*p is not an error when p is null unless the lvalue is converted to an rvalue." However, that relies on the concept of an "empty lvalue," which is part of the proposed resolution to CWG defect 232, but which has not been adopted. So, wit...
What is the standard naming convention for html/css ids and classes?
... by id easily in like that. But if you use a hyphen it will cause a syntax error.
This is an old sample, but it can work without jquery -:)
thanks to @jean_ralphio, there is work around way to avoid by
var x = document.myForm['my-Id'].value;
Dash-style would be a google code style, but I don't...
Undefined, unspecified and implementation-defined behavior
...e in a predictable way, even though many C++ compilers will not report any errors in the program!
Let's look at a classic example:
#include <iostream>
int main()
{
char* p = "hello!\n"; // yes I know, deprecated conversion
p[0] = 'y';
p[5] = 'w';
std::cout << p;
}
The...