Why can’t we initialize members inside a structure ? example: struct s { int i = 10; }; Answer 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) { … Read more
In C++, why is private the default visibility for members of classes, but public for structs? Answer 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 … Read more
I know that inline member functions by definition should go into the header. But what if it’s not possible to put the implementation of the function into the header? Let’s take this situation: File A.h #pragma once #include “B.h” class A{ B b; }; File B.h #pragma once class A; //forward declaration class B{ inline … Read more
This question already has answers here: Closed 9 years ago. I created a class called Kwadrat. The class has three int fields. My Development Environment suggests that I access the fields from Kwadrat created objects via the :: & -> operators. I tried both operators, and found that the -> operator is able to successfully … Read more
I know this has been asked so many times, and because of that it’s difficult to dig through the cruft and find a simple example of what works. I’ve got this, it’s simple and it works for MyClass… #include <iostream> using std::cout; using std::endl; class MyClass { public: MyClass(); static void Callback(MyClass* instance, int x); … Read more
I have a question regarding static function in php. let’s assume that I have a class class test { public function sayHi() { echo ‘hi’; } } if I do test::sayHi(); it works without a problem. class test { public static function sayHi() { echo ‘hi’; } } test::sayHi(); works as well. What are the … Read more
I have Python classes, of which I need only one instance at runtime, so it would be sufficient to have the attributes only once per class and not per instance. If there would be more than one instance (which won’t happen), all instance should have the same configuration. I wonder which of the following options … Read more
Very simply put: I have a class that consists mostly of static public members, so I can group similar functions together that still have to be called from other classes/functions. Anyway, I have defined two static unsigned char variables in my class public scope, when I try to modify these values in the same class’ … Read more
I was looking at the Java code for LinkedList and noticed that it made use of a static nested class, Entry. public class LinkedList<E> … { … private static class Entry<E> { … } } What is the reason for using a static nested class, rather than an normal inner class? The only reason I … Read more
I’m practicing using mulitple files and header files etc. So I have this project which takes two numbers and then adds them. Pretty simple. Here are my files: main.cpp #include <iostream> #include “add.h” int main() { int x = readNumber(); int y = readNumber(); writeAnswer(x + y); return(0); } io.cpp int readNumber() { int x; … Read more
