Static members are different for each diffrent template initialization. This is because each template initialization is a different class that is generated by the compiler the first time it encounters that specific initialization of the template. The fact that static member variables are different is shown by this code: #include <iostream> template <class T> class … Read more
Once the anonymous class instance has been implicitly cast into the named type it can’t be cast back because there is no name for the anonymous type. You can access the additional members of the anonymous inner class through this within the class, in the expression immediate after the expression and the type can be … Read more
You need to call a(int) explicitly in the constructor initializer list: b() : aInstance(3) {} Where 3 is the initial value you’d like to use. Though it could be any int. See comments for important notes on order and other caveats.
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
var should definitely not be shared as long as you access it by instance.var or self.var. With the list however, what your statement does is when the class gets evaluated, one list instance is created and bound to the class dict, hence all instances will have the same list. Whenever you set instance.list = somethingelse … Read more
It’s 0. It can’t be null, as null isn’t a valid int value. From section 7.6.10.4 of the C# 5 specification: All elements of the new array instance are initialized to their default values (§5.2). And from section 5.2: The default value of a variable depends on the type of the variable and is determined … 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
Quoting from C++ FAQ: Note: It’s imperative that the function’s definition (the part between the {…}) be placed in a header file, unless the function is used only in a single .cpp file. In particular, if you put the inline function’s definition into a .cpp file and you call it from some other .cpp file, … Read more
At the time you declare your member, you are still defining the A class, so the type A is still undefined. However, when you write A*, the compiler already knows that A stands for a class name, and so the type “pointer to A” is defined. That’s why you can embed a pointer to the … Read more
The Sun page you link to has some key differences between the two: A nested class is a member of its enclosing class. Non-static nested classes (inner classes) have access to other members of the enclosing class, even if they are declared private. Static nested classes do not have access to other members of the … Read more