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Why are #ifndef and #define used in C++ header files?
...his case HEADERFILE_H) is defined. Then if it's not defined, it defines it and continues to the rest of the page.
When the code is included again, the first ifndef fails, resulting in a blank file.
That prevents double declaration of any identifiers such as types, enums and static variables.
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Why is [1,2] + [3,4] = “1,23,4” in JavaScript?
...d for arrays.
What happens is that Javascript converts arrays into strings and concatenates those.
Update
Since this question and consequently my answer is getting a lot of attention I felt it would be useful and relevant to have an overview about how the + operator behaves in general also.
So, h...
Restoring Nuget References?
...he packages.
In the NuGet Package Manager Console enter the following command:
Update-Package -Reinstall -ProjectName Your.Project.Name
If you want to re-install packages and restore references for the whole solution omit the -ProjectName parameter.
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Combining C++ and C - how does #ifdef __cplusplus work?
...convert the legacy code, as well. I'm a little confused about how the C and C++ interact. I understand that by wrapping the C code with extern "C" the C++ compiler will not mangle the C code's names, but I'm not entirely sure how to implement this.
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Is there a best practice for generating html with javascript
...ce that returns an array of objects in JSON. I want to take those objects and populate a div with HTML. Let's say each object contains a url and a name.
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Checkout old commit and make it a new commit [duplicate]
On Git, say I mess up my commits, and I want to make the version 3 commits ago as the new version. If I do git checkout xxxx , it creates a new branch and it seems like I can only merge it? Could I make this the new "master version"?
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How do I specify different layouts for portrait and landscape orientations?
...to specify two separate layout xml files for an activity, one for Portrait and one for Landscape. I've not been to find any information on how to do that though. How do I specify for each activity which xml file is it's portrait layout and which is the Landscape layout?
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What is Serialization?
I am getting started with Object-Oriented Programming (OOP) and would like to know: what is the meaning of serialization in OOP parlance?
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Git commit with no commit message
...providing a meaningful commit message is part of good development practice and good repository stewardship. The first line of the commit message is used all over the place within git; for more, read "A Note About Git Commit Messages".
If you open Terminal.app, cd to your project directory, and git ...
Why is my git repository so big?
... pulled the wrong remote repository into the local one (git remote add ... and git remote update). After deleting the unwanted remote ref, branches and tags I still had 1.4GB (!) of wasted space in my repository. I was only able to get rid of this by cloning it with git clone file:///path/to/repos...