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Why would I ever use push_back instead of emplace_back?
...ies on compiler optimizations to avoid copies, emplace_back uses perfect forwarding to send the arguments directly to the constructor to create an object in-place. It seems to me that emplace_back does everything push_back can do, but some of the time it will do it better (but never worse).
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Is there any advantage of using map over unordered_map in case of trivial keys?
...t unordered_map in C++ made me realize that I should use unordered_map for most cases where I used map before, because of the efficiency of lookup ( amortized O(1) vs. O(log n) ). Most times I use a map, I use either int or std::string as the key type; hence, I've got no problems with ...
Hook up Raspberry Pi via Ethernet to laptop without router? [closed]
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It's a solution for Ubuntu (the idea also works for Windows or Mac) I just tried today and it works like a charm.
Material
a cross-over Ethernet cable (the name is fancy but it's just a normal Ethernet cable)
a laptop (ubuntu)
a Raspberr...
How to reliably guess the encoding between MacRoman, CP1252, Latin1, UTF-8, and ASCII
...a to determine whether the cp1252 or MacRoman characters are more common.
For example, in a search I just performed on 100 random English Wikipedia articles, the most common non-ASCII characters are ·•–é°®’èö—. Based on this fact,
The bytes 0x92, 0x95, 0x96, 0x97, 0xAE, 0xB0, 0xB7,...
Avoiding if statement inside a for loop?
... the body of the loop as a functor. It gets inlined at compile-time, no performance penalty.
The idea of passing in what varies is ubiquitous in the C++ Standard Library. It is called the strategy pattern.
If you are allowed to use C++11, you can do something like this:
#include <iostream>...
Things possible in IntelliJ that aren't possible in Eclipse?
... including other .js files and JS code in HTML or JSP files.
Autocomplete for many languagues
Hibernate
Autocomplete in HSQL expressions, in Hibernate configuration (including class, property and DB column names), in Spring configuration
<property name="propName" ref="<hit CTRL-SPACE>"
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Why doesn't GCC optimize a*a*a*a*a*a to (a*a*a)*(a*a*a)?
... actually call the library function pow , which greatly slows down the performance. (In contrast, Intel C++ Compiler , executable icc , will eliminate the library call for pow(a,6) .)
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How to create the most compact mapping n → isprime(n) up to a limit N?
Naturally, for bool isprime(number) there would be a data structure I could query.
I define the best algorithm , to be the algorithm that produces a data structure with lowest memory consumption for the range (1, N], where N is a constant.
Just an example of what I am looking for: I could rep...
Determine a string's encoding in C#
....com
Notice: as already pointed out "determine encoding" makes sense only for byte streams. If you have a string it is already encoded from someone along the way who already knew or guessed the encoding to get the string in the first place.
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Is MATLAB OOP slow or am I doing something wrong?
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I've been working with OO MATLAB for a while, and ended up looking at similar performance issues.
The short answer is: yes, MATLAB's OOP is kind of slow. There is substantial method call overhead, higher than mainstream OO languages, and there's not much yo...