default

I cannot understand the behavior of gcc 4.8.1 or Visual Studio 2015 with respect to default initialization versus value initialization. It doesn't help that I'm trying to understand the differences between these myself and possibly running into compiler bugs? My question is: Can someone explain this behavior? And ideally tell me what should be happening. I have two classes: class Foo{ int _bar; public: void printBar(){ cout << _bar << endl; } }; class bar{ int ent; public: int getEnt(){return ent;} }; I'm using the following code to test: int main() { Foo foo; foo.printBar(); Foo().printBar();

These are my class definitions: class Foo{ int _ent; public: void printEnt() const{cout << _ent << ' ';} }; class Bar{ Foo _foo; public: void printEnt() const{_foo.printEnt();} }; And this is my test code: char* buf = new char[sizeof(Foo) + sizeof(Foo) + sizeof(Bar)]; fill(buf, buf + sizeof(Foo) + sizeof(Foo) + sizeof(Bar), 'J'); cout << ((int*)buf)[0] << ' ' << ((int*)buf)[1] << ' ' << ((int*)buf)[2] << endl; Foo* first = new (buf) Foo; Foo* second = new (buf + sizeof(Foo)) Foo(); Bar* third = new (buf + sizeof(Foo) * 2) Bar; first->printEnt(); second->printEnt(); third->printEnt(); My output

I have protocol and his implementation written in Swift: protocol P { } struct A: P { } Protocol is used as generic type for some function: func foo<T: P>(param: T) { } func foo() { foo(param: A()) } Until now everything works properly. But I would like to set A() as a default parameter of given function: func foo<T: P>(param: T = A()) { } Unfortunately with following error: Default argument value of type 'A' cannot be converted to type 'T'. Or func foo<T: P>(param: T = A() as P) { } , let a: P = A() func foo<T: P>(param: T = a) { } Returns: Default argument value of type 'P' cannot be

Can I use default arguments in a constructor like this maybe Soldier(int entyID, int hlth = 100, int exp = 10, string nme) : entityID(entyID = globalID++), health(hlth), experience(exp), name(nme = SelectRandomName(exp)) { } I want for example exp = 10 by default but be able to override this value if I supply it in the constructor otherwise it should use the default. How can I do this, I know my approach does not work.... If I supply any value in the initialization list no matter whatever I supply in constructor gets overwritten ofcourse on the other hand whenever I supply a value in

I'm trying to learn and grasp what and how C# does things. I'm historically a Visual Foxpro (VFP) developer, and somewhat spoiled at the years of visual inheritance by creating my own baseline of user controls to be used application wide. In trying to learn the parallels in C#, I am stuck on something. Say I derive my own label control (control is subclass of label) defined with a font "Arial", 10 point. Then, on any form I add it to, the Designer will automatically pre-fill in some property values which can be seen in the "Designer.cs" portion of the Form class. this.LabelHdr2.AutoSize = true