help

[hearty thistle]

What does : mean here in constructor? Is it some kind of way to inherit something in constructor declaration?

GeneralizedEigenSolver()
      : m_eivec(),
        m_alphas(),
        m_betas(),
        m_computeEigenvectors(false),
        m_isInitialized(false),
        m_realQZ()
    {}

Original source code: https://gitlab.com/libeigen/eigen/-/blob/master/Eigen/src/Eigenvalues/GeneralizedEigenSolver.h

[dense solar]

When your question is answered use !solved to mark the question as resolved.

Remember to ask specific questions, provide necessary details, and reduce your question to its simplest form. For more information use !howto ask.

[patent cave]

Its special way of initializing member variables. I dont know what exactly its called and what are the benefits but e.g. you can initialize a pointer:

In hpp:

public:
   Class(int* tmp);

private:
   int* m_pointer;

In cpp:

Class::Class(int* tmp) : m_pointer(tmp)
{
}

Now the member variable m_pointer points to the same like tmp does.

https://www.open-std.org/JTC1/SC22/WG21/docs/papers/2008/n2756.htm

Seems like its called an "initialization list"

[heavy spire]

that is the initializer list of the constructor, it is used to call existing constructors (C++11), call constructors of base classes when inheritance is used, and initialize your variables directly, this is important for fields which are objects because instead of running default constructor and operator=, you just run one constructor and you are done

[patent cave]

Better and more detailed than my explanation👍🏼

[heavy spire]

you are correct human

[patent cave]

Yours is more professional :P

[acoustic adder]

https://www.educative.io/answers/what-are-initializer-lists-in-cpp initializer-lists

[hearty thistle]

well. then m_name is a convention to call private variables, in this case?

[heavy spire]

well... yea but that convention is kinda useless

inside the body of a constructor, function, whatever, to access a field you have 3 options

the field name literally - works well unless there are local variables or function parameters reusing the name

this->myFieldName works well, handles duplicate names with local variables and function parameters, but not with duplicate field names coming from inherited classes

MyClassName::myFieldName

the only approach guaranteed to NOT be amibguous in all the situations

@hearty thistle

this is a pointer to the current object you are working with, the pointer cannot be redirected

also, this is a keyword in C++

[dense solar]

You can only solve threads you own

[hearty thistle]

!resolve

!solve

!solved