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SQL left join vs multiple tables on FROM line?
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The old syntax, with just listing the tables, and using the WHERE clause to specify the join criteria, is being deprecated in most modern databases.
It's not just for show, the old syntax has the possibility of being ambiguous when you use both INNER and OUTER joins in ...
For-each over an array in JavaScript
...-of loop (ES2015+ only),
Array#forEach (spec | MDN) (or its relatives some and such) (ES5+ only),
a simple old-fashioned for loop,
or for-in with safeguards.
But there's lots more to explore, read on...
JavaScript has powerful semantics for looping through arrays and array-like objects. I've s...
Why is String immutable in Java?
...it were mutable, these parameters could be easily changed.
Synchronization and concurrency: making String immutable automatically makes them thread safe thereby solving the synchronization issues.
Caching: when compiler optimizes your String objects, it sees that if two objects have same value (a="...
SQL Server IN vs. EXISTS Performance
...t. The IN statement requires SQL Server to generate a complete result set, and then create a big IF statement I think.
– Randy Minder
Jan 14 '10 at 16:04
74
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What's the difference between an argument and a parameter?
...ng else. Either way the other people know what I mean, but what's correct, and what's the history of the terms?
34 Answers
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Easy interview question got harder: given numbers 1..100, find the missing number(s) given exactly k
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Here's a summary of Dimitris Andreou's link.
Remember sum of i-th powers, where i=1,2,..,k. This reduces the problem to solving the system of equations
a1 + a2 + ... + ak = b1
a12 + a22 + ... + ak2 = b2
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a1k + a2k + ... + akk = bk
Using Newton's...
Elegant solution to duplicate, const and non-const, getters? [duplicate]
...e member function calling it is non-const, the object itself is non-const, and casting away the const is allowed.
class Foo
{
public:
const int& get() const
{
//non-trivial work
return foo;
}
int& get()
{
return const_cast<int&>(const_c...
How to convert AAR to JAR
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The AAR file consists of a JAR file and some resource files (it is basically a standard zip file with a custom file extension). Here are the steps to convert:
Extract the AAR file using standard zip extract (rename it to *.zip to make it easier)
Find the clas...
What is a semaphore?
...t should let the guests go in sequentially, but when i tried it out, it's random. Eg. Guest 40 came in first before Guest 39. Is there anything we could do to control this?
– TNA
May 31 '14 at 9:12
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Cosmic Rays: what is the probability they will affect a program?
Once again I was in a design review, and encountered the claim that the probability of a particular scenario was "less than the risk of cosmic rays" affecting the program, and it occurred to me that I didn't have the faintest idea what that probability is.
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