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The role of #ifdef and #ifndef
...Text inside an ifdef/endif or ifndef/endif pair will be left in or removed by the pre-processor depending on the condition. ifdef means "if the following is defined" while ifndef means "if the following is not defined".
So:
#define one 0
#ifdef one
printf("one is defined ");
#endif
#ifndef one...
Where should Rails 3 custom validators be stored?
...ld go in a /lib or /lib/validators directory of a project. I've found (by reading an answer to another post) that they only seem to work in config/initializers . Does anyone know, or have a pointer to official documentation that shows where custom validators should live?
...
How do you write a migration to rename an ActiveRecord model and its table in Rails?
...thee: yes, you have to change that manually, or using an IDE that can do Ruby refactoring and commit it to your version control system.
– pupeno
Apr 30 '10 at 9:00
13
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Assembly code vs Machine code vs Object code?
...
Machine code is binary (1's and 0's) code that can be executed directly by the CPU. If you were to open a machine code file in a text editor you would see garbage, including unprintable characters (no, not those unprintable characters ;) ).
Object code is a portion of machine code not yet linked ...
Extracting substrings in Go
...
It looks like you're confused by the working of slices and the string storage format, which is different from what you have in C.
any slice in Go stores the length (in bytes), so you don't have to care about the cost of the len operation : there is no n...
How might I convert a double to the nearest integer value?
...
@Ronnie - nope, that's by design. By default, Math.Round will round midpoint numbers (x + .5) to the nearest even number. If you want a different behaviour, you have to specify it via a flag. msdn.microsoft.com/en-us/library/system.midpointrounding...
How can I find the data structure that represents mine layout of Minesweeper in memory?
...to find window message handling procedure (WndProc). It can be traced down by CreateWindowEx and RegisterClass calls.
To read:
CreateWindowEx http://msdn.microsoft.com/en-us/library/ms632680%28VS.85%29.aspx
RegisterClass http://msdn.microsoft.com/en-us/library/ms633586%28VS.85%29.aspx
Petzold's C...
How to count the number of set bits in a 32-bit integer?
...re the CPU has to fetch some of the table from main memory. (Look up each byte separately to keep the table small.)
If you know that your bytes will be mostly 0's or mostly 1's then there are very efficient algorithms for these scenarios.
I believe a very good general purpose algorithm is the follo...
MySQL Fire Trigger for both Insert and Update
...'t use AND/OR operators like in Oracle, even more when we also can't pass by parameter to a procedure the whole variables OLD and NEW. My code will be > 2x
– Mikel
Nov 26 '13 at 8:13
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Logging framework incompatibility
...orts for other SLF4J versions on this page.
You can generate such reports by the japi-compliance-checker tool.
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