FAQ Database Discussion Community


C++: Store pointer to a member function of an object in another object

c++,templates,function-pointers,member-functions
I have a class which shall invoke a function specified by the user on certain occasions. Therefore the class has a method void setExternalPostPaintFunction(void(*function)(QPainter&)); that can be used to "register" a function. This function then will be called on that occasion: class A { public: void setExternalPostPaintFunction(void(*function)(QPainter&)); private: void (*_externalPostPaint)(QPainter&);...

Passing a C++ Member Function Pointer to an STL Algorithm

c++,stl,member-functions,stl-algorithm
I have a member function as follows: class XYZ{ public: float function(float x); private: float m_DensityMin; float m_DensityMax; }; Now, I'm trying to transform a std::vector<float> foo using the std::transform STL algorithm by passing the member function function, and storing the resulting values in a vector bar. If I use...

Correct function signature template for member function

c++,templates,variadic-templates,member-functions
Following up on a question I recently asked, there might be some unnecessary stuff in there but the example is small, what I want to do (and of course if you can think of other cool ways to do this, please share your thoughts), is to allow the user to...

What happens when a member function with no arguments is called by an object in c++

c++,member-functions,this-pointer
Suppose we have a member function of class X and it is X f() which returns an object of class X and takes no arguments. So if it is called by an object of class X, say X obj is the object. So if we call obj.f(), so as per...

C++ Callback Function to Member Function

c++,function,callback,member-function-pointers,member-functions
I have never worked with callbacks, but the following code should work according to my professor's notes. It doesn't like the template and has errors about "gauss cannot appear in a constant-expression." Note: GaussElim is a function object (gauss(mx, vector) works in previous code). The DirichletSolver templated callback function: template...

Compile time deduction of template member function

templates,c++11,member-functions
Is it possible to get the return type of a template member function at compile time? I guess I need something along the lines of: template<class T> struct SomeClass { // T must have a function foo(int), but do not know the // return type, it could be anything using...

C++, template or pointer to member function

c++,templates,boost,member-functions
I have a series of member functions that are all very similar, and I think I might be able to make my code more maintainable with a template or some other approach, but I am not sure how to do it. Here is an example of one of my functions:...

Defining unnamed class member functions?

c++,class,definition,member-functions
I currently have two unnamed classes defined in my Foo.h: class Foo { public: Foo(); class { private: int x; int y; public: int GetX() { return x; } int GetY() { return y; } } Sub1; class { private: int x; public: int GetX() { return x; } }...

Private member variable is null when passed from constructor to member function

c++,class,oop,member-functions
I'm pretty new to OOP in c++ so bear with me here. In my header that defines my member variables; class AntibodyJunction { private: //raw seq seqan::Dna5 _raw_sequence; //private funcs void _setVGeneQueryStartTranslation(); public: //V D and J constructor AntibodyJunction(AlignAntibody &, AlignAntibody &, AlignAntibody &, seqan::Dna5 &); ~AntibodyJunction() {}; }; and...

Initialize a const vector in a class constructor (C++)

c++,class,vector,const,member-functions
I am trying to figure out how to initialize a const class member variable, (in this case a vector), to some arbitrary values in the class's constructor. Basically, in the class definition, I have: const vector < pair <float, float> > myVector; In the class's constructor however, I would like...