If you have only one instance anyway, it’s best to make all variables per-instance, simply because they will be accessed (a little bit) faster (one less level of “lookup” due to the “inheritance” from class to instance), and there are no downsides to weigh against this small advantage.
You need to use the constructor initializer list: CamFeed::CamFeed(ofVideoGrabber& cam) : cam(cam) {} This is because references must refer to something and therefore cannot be default constructed. Once you are in the constructor body, all your data members have been initialized. Your this->cam = cam; line would really be an assignment, assigning the value referred … Read more
In C++, identifiers starting with an underscore, followed by a capital character identifiers having two consecutive underscores anywhere identifiers in the global namespace starting with an underscore are reserved to the implementation. (More about this can be found here.) Rather than trying to remember these rules, many simply do not use identifiers starting with an … Read more
If A is a class, you can access it directly via A::$strName. class A { public static $strName=”A is my name”; } echo A::$strName; // outputs “A is my name” Update: Depending on what you have inside your array, whether its what I like to define as class objects or class literals could be a … Read more
If I create a class MyClass and it has some private member say MyOtherClass, is it better to make MyOtherClass a pointer or not? you should generally declare it as a value in your class. it will be local, there will be less chance for errors, fewer allocations — ultimately fewer things that could go … Read more
This paper was adopted into C++17 which allows incomplete types to be used in certain STL containers. Prior to that, it was Undefined Behavior. To quote from the paper: Based on the discussion on the Issaquah meeting, we achieved the consensus to proceed* with the approach – “Containers of Incomplete Types”, but limit the scope … Read more
If you want to initialize non-static members in struct declaration: In C++ (not C), structs are almost synonymous to classes and can have members initialized in the constructor. struct s { int i; s(): i(10) { } }; If you want to initialize an instance: In C or C++: struct s { int i; }; … Read more
In Kotlin, nested classes cannot access the outer class instance by default, just like nested static classes can’t in Java. To do that, add the inner modifier to the nested class: class MainFragment : Fragment() { // … inner class PersonAdapter() : RecyclerView.Adapter<ViewHolder>() { // … } } Note that an inner class holds a … Read more
The dot operator is used for accessing attributes of any object. For example, a complex number >>> c = 3+4j has (among others) the two attributes real and imag: >>> c.real 3.0 >>> c.imag 4.0 As well as those, it has a method, conjugate(), which is also an attribute: >>> c.conjugate <built-in method conjugate of … Read more
C++ was introduced as a superset of C. Structs were carried over from C, where the semantics of their members was that of public. A whole lot of C code exists, including libraries that were desired to work with C++ as well, that use structs. Classes were introduced in C++, and to conform with the … Read more