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Why does Java's hashCode() in String use 31 as a multiplier?
...to Joshua Bloch's Effective Java (a book that can't be recommended enough, and which I bought thanks to continual mentions on stackoverflow):
The value 31 was chosen because it is an odd prime. If it were even and the multiplication overflowed, information would be lost, as multiplication by 2 i...
Java: What is the difference between and ?
I am unable to understand the following text... Does it mean that <clinit> is for empty constructors? Why is important to have two different versions?
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omp parallel vs. omp parallel for
...r
specifying a parallel construct containing one worksharing construct
and no other statements. Permitted clauses are the union of the clauses
allowed for the parallel and worksharing contructs.
Taken from http://www.openmp.org/mp-documents/OpenMP3.0-SummarySpec.pdf
The specs for OpenMP are...
Swapping two variable value without using third variable
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*x ^= *y;
}
}
Why the test?
The test is to ensure that x and y have different memory locations (rather than different values). This is because (p xor p) = 0 and if both x and y share the same memory location, when one is set to 0, both are set to 0.
When both *x and *y are 0, all o...
How can I do DNS lookups in Python, including referring to /etc/hosts?
...for the late comment: the result may be cached by the local resolver. nscd and nslcd on Unix boxes can do this. It could also be cached by a local name server configured for caching (a common setup, once upon a time. Probably not so much now). It's not a straightforward ‘no’ answer, unfortunatel...
Why are Python lambdas useful? [closed]
...se elements of the original list that are multiples of 3. This is shorter (and, one could argue, clearer) than
def filterfunc(x):
return x % 3 == 0
mult3 = filter(filterfunc, [1, 2, 3, 4, 5, 6, 7, 8, 9])
Of course, in this particular case, you could do the same thing as a list comprehension:
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When does invoking a member function on a null instance result in undefined behavior?
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Both (a) and (b) result in undefined behavior. It's always undefined behavior to call a member function through a null pointer. If the function is static, it's technically undefined as well, but there's some dispute.
The first thin...
Difference between parameter and argument [duplicate]
Is there a difference between a "parameter" and an "argument", or are they simply synonyms?
4 Answers
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Meaning of = delete after function declaration
...'t the traditional method to "prohibit copying" just to make the copy-ctor and operator= "private?" This goes a bit further and instructs the compiler to not even generate the functions. If they're both private and =delete, is copying doubly-prohibited?
– Reb.Cabin
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What is meant by Scala's path-dependent types?
.... It's something to do with inner-classes but what does this actually mean and why do I care?
1 Answer
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