superclass

In python, whenever we are writing User-defined exception, we have to extend it from class Exception . my question is why can't we extend it from BaseException which is super-class of exception hierarchy and Exception is also subclass of BaseException . BaseException includes things like KeyboardInterrupt and SystemExit , which use the exception mechanism, but which most people shouldn't be catching. It's analogous to Throwable in Java, if you're familiar with that. Things that derive directly from BaseException are generally intended to shut down the system while executing finally blocks and

Hi I'm wondering if there is a simple solution to my problem, I have an ArrayList : ArrayList <Animal> animalList = new ArrayList<Animal>(); /* I add some objects from subclasses of Animal */ animalList.add(new Reptile()); animalList.add(new Bird()); animalList.add(new Amphibian()); They all implement a method move() - The Bird flies when move() is called. I know I can access common methods and properties of the super class by using this public void feed(Integer animalIndex) { Animal aAnimal = (Animal) this.animalList.get(animalIndex); aAnimal.eat(); } That's fine - but now I would like to

Is there a standard CPAN way of finding out all the superclasses of a Perl class (or better yet entire superclass tree, up to UNIVERSAL)? Or is the best practice to simply examine @{"${$class}::ISA"} for each class, class's parents etc...? There is no "standard way" because this is not a standard thing you want to do. For anything other than visualization it is an OO red flag to want to inspect your inheritance tree. In addition to Class::ISA, there is mro::get_linear_isa() . Both have been in core for a while so they could be considered "standard" for some definition. Both of those show

I get a compile error, which I'm slightly confused about. This is on VS2003. error C2248: 'A::y' : cannot access protected member declared in class 'A' class A { public: A() : x(0), y(0) {} protected: int x; int y; }; class B : public A { public: B() : A(), z(0) {} B(const A& item) : A(), z(1) { x = item.y;} private: int z; }; The problem is with x = item.y; The access is specified as protected. Why doesn't the constructor of class B have access to A::y? It's because of this: class base_class { protected: virtual void foo() { std::cout << "base::foo()" << std::endl; } }; class A : public base

While creating a java program i encountered a problem, A subclass constructor is throwing an Error by calling the Superclass's method The code is similar to this : class Manage { public static void main(String[] args) { Manager m1 = new Manager ( 35 ); } } class Employee { int emp_id; public Employee(int id) { this.emp_id = id; } public int get_id() { return emp_id; } } class Manager extends Employee { public Manager(int id ) { this.emp_id = id ; } } class Engineer extends Employee { public Engineer(int id) { this.emp_id = id ; } } And the error is something like this : $ javac app.java app

I have created a slide out menu using Swift. I have done this many times before, but when I created it today, I get this error (see screenshot). It could just be a simple mistake I have made. Here is the code, that I think is causing the problem: override func tableView(tableView: UITableView!, cellForRowAtIndexPath indexPath: NSIndexPath!) -> UITableViewCell! { var cell:UITableViewCell? = tableView.dequeueReusableCellWithIdentifier("Cell")! as UITableViewCell if cell == nil{ cell = UITableViewCell(style: UITableViewCellStyle.Default, reuseIdentifier: "Cell") cell!.backgroundColor = UIColor

I'd like to call a parent's call method from inherited class Code looks like this #!/usr/bin/env python class Parent(object): def __call__(self, name): print "hello world, ", name class Person(Parent): def __call__(self, someinfo): super(Parent, self).__call__(someinfo) p = Person() p("info") And I get, File "./test.py", line 12, in __call__ super(Parent, self).__call__(someinfo) AttributeError: 'super' object has no attribute '__call__' And I can't figure out why, can somebody please help me with this? The super function takes the derived class as its first parameter, not the base class.