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What is the fastest way to compute sin and cos together?
...this by using complex numbers and Euler’s Formula. Thus, something like (C++)
complex<double> res = exp(complex<double>(0, x));
// or equivalent
complex<double> res = polar<double>(1, x);
double sin_x = res.imag();
double cos_x = res.real();
should give you sine and cosi...
Node.js or Erlang
...
According to the docs, Node.js can leverage C and C++ for external addons. nodejs.org/docs/v0.3.1/api/addons.html
– Evan Plaice
Jan 24 '12 at 21:13
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Pimpl idiom vs Pure virtual class interface
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When writing a C++ class, it's appropriate to think about whether it's going to be
A Value Type
Copy by value, identity is never important. It's appropriate for it to be a key in a std::map. Example, a "string" class, or a "date" class, or...
How do I output coloured text to a Linux terminal?
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Basics
I have written a C++ class which can be used to set the foreground and background color of output. This sample program serves as an example of printing This ->word<- is red. and formatting it so that the foreground color of word is red....
What is the difference between float and double?
...Otherwise, try to implement the Kahan summation algorithm.
[1]: The C and C++ standards do not specify the representation of float, double and long double. It is possible that all three are implemented as IEEE double-precision. Nevertheless, for most architectures (gcc, MSVC; x86, x64, ARM) float i...
How to forward declare a template class in namespace std?
...ementing an OSI Layer (slider window, Level 2) for a network simulation in C++ (Eclipse Juno). I had frames (template <class T>) and its states (state pattern, forward declaration).
The solution is as follows:
In the *.cpp file, you must include the Header file that you forward, i.e.
ifndef...
Why can't I define a default constructor for a struct in .NET?
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Shorter explanation: In C++, struct and class were just two sides of the same coin. The only real difference is one was public by default and the other was private. In .Net, there is a much greater difference between a struct and a class, and it's...
What is the difference between Cygwin and MinGW?
I want to make my C++ project cross platform, and I'm considering using Cygwin/MinGW.
But what is the difference between them ?
...
What does the explicit keyword mean?
What does the explicit keyword mean in C++?
11 Answers
11
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Does the 'mutable' keyword have any purpose other than allowing the variable to be modified by a con
...tes a value the first time it is requested, and caches the result.
Since c++11 mutable can be used on a lambda to denote that things captured by value are modifiable (they aren't by default):
int x = 0;
auto f1 = [=]() mutable {x = 42;}; // OK
auto f2 = [=]() {x = 42;}; // Error: a by-v...