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Why covariance and contravariance do not support value type
...or not.
You might want to read Eric Lippert's blog post on representation and identity for more on this topic in general.
EDIT: Having reread Eric's blog post myself, it's at least as much about identity as representation, although the two are linked. In particular:
This is why covariant and ...
Difference between HEAD and master
What is the difference between the HEAD and master in Git?
3 Answers
3
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What does the “__block” keyword mean?
...eated in a special way when it is used inside a block. Normally, variables and their contents that are also used in blocks are copied, thus any modification done to these variables don't show outside the block. When they are marked with __block, the modifications done inside the block are also visib...
undefined reference to boost::system::system_category() when compiling
...do.)
Assuming you use gcc, try adding -lboost_system to your compiler command line in order to link against that library.
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Boolean vs boolean in Java
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Yes you can use Boolean/boolean instead.
First one is Object and second one is primitive type.
On first one, you will get more methods which will be useful.
Second one is cheap considering memory expense The second will save you a lot more memory, so go for it
Now choose your way....
What is the most efficient way of finding all the factors of a number in Python?
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The reduce(list.__add__, ...) is taking the little lists of [fac1, fac2] and joining them together in one long list.
The [i, n/i] for i in range(1, int(sqrt(n)) + 1) if n % i == 0 returns a pair of factors if the remainder when you divide n by the smaller one is zero (it doesn't need to check the...
SQL “between” not inclusive
...:
SELECT *
FROM Cases
WHERE cast(created_at as date) BETWEEN '2013-05-01' AND '2013-05-01'
Another way to fix it is with explicit binary comparisons
SELECT *
FROM Cases
WHERE created_at >= '2013-05-01' AND created_at < '2013-05-02'
Aaron Bertrand has a long blog entry on dates (here), wh...
Confused about stdin, stdout and stderr?
I am rather confused with the purpose of these three files. If my understanding is correct, stdin is the file in which a program writes into its requests to run a task in the process, stdout is the file into which the kernel writes its output and the process requesting it accesses the informatio...
Flask vs webapp2 for Google App Engine
I'm starting new Google App Engine application and currently considering two frameworks: Flask and webapp2 . I'm rather satisfied with built-in webapp framework that I've used for my previous App Engine application, so I think webapp2 will be even better and I won't have any problems with it.
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I want to get Year, Month, Day, etc from Java Date to compare with Gregorian Calendar date in Java.
....add(Calendar.DAY_OF_MONTH, -48) to do day arithmetic on Calendar objects. And you can compare two Calendar objects using cal.compareTo(anotherCal).
– Florent Guillaume
Feb 27 '12 at 23:55
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