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When should I use the Visitor Design Pattern? [closed]
...want to make the fewest possible modifications to it.
The Visitor pattern allows you to move each new operation in a suitable class, and you need to extend the hierarchy's interface only once. Let's do it. First, we define an abstract operation (the "Visitor" class in GoF) which has a method for ev...
Comma in C/C++ macro
...his is also a problem for square brackets and braces, even though those usually occur as balanced pairs.) You can enclose the macro argument in parentheses:
FOO((std::map<int, int>), map_var);
The problem is then that the parameter remains parenthesized inside the macro expansion, which pr...
Checking a Python module version at runtime
...s have an attribute which holds the version information for the module (usually something like module.VERSION or module.__version__ ), however some do not.
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How do I find files with a path length greater than 260 characters in Windows?
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See my answer for a way to achieve this in powershell, allowing you to either find the offending file names (those above 260 characters) or alternatively, ignore them.
– Jonno
Oct 18 '15 at 12:11
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Why does += behave unexpectedly on lists?
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The general answer is that += tries to call the __iadd__ special method, and if that isn't available it tries to use __add__ instead. So the issue is with the difference between these special methods.
The __iadd__ special method is for an in-place addition, that i...
Objective-C declared @property attributes (nonatomic, copy, strong, weak)
... retaining the copy.
Assign
Assign is somewhat the opposite to copy. When calling the getter of an assign property, it returns a reference to the actual data. Typically you use this attribute when you have a property of primitive type (float, int, BOOL...)
Retain
retain is required when the attribut...
How can I hash a password in Java?
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You can actually use a facility built in to the Java runtime to do this. The SunJCE in Java 6 supports PBKDF2, which is a good algorithm to use for password hashing.
byte[] salt = new byte[16];
random.nextBytes(salt);
KeySpec spec = new...
Get all related Django model objects
How can I get a list of all the model objects that have a ForeignKey pointing to an object? (Something like the delete confirmation page in the Django admin before DELETE CASCADE).
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Recursive file search using PowerShell
I am searching for a file in all the folders.
8 Answers
8
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How does JavaScript .prototype work?
...ing languages but I've written my fair share of JavaScript code. I never really got my head around this prototype-based programming, does any one know how this works?
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