superclass

This question already has an answer here: Interface vs Abstract Class (general OO) 34 answers Lately i decided to take a look at Java so i am still pretty new to it and also to the approach of OO programming, so i wanted to get some things straight before learning more, (i guess it's never to soon to start with good practices). I am programming a little 2D game for now but i think my question applies to any non trivial project. For the simplicity I'll provide examples from my game. I have different kinds of zombies, but they all have the same attributes (x, y, health, attack etc) so i wrote an

I'm dealing with a class which extends JFrame . It's not my code and it makes a call to super before it begins constructing the GUI. I'm wondering why this is done since I've always just accessed the methods of the superclass without having to call super(); There is an implicit call to super() with no arguments for all classes that have a parent - which is every user defined class in Java - so calling it explicitly is usually not required. However, you may use the call to super() with arguments if the parent's constructor takes parameters, and you wish to specify them. Moreover, if the parent

Why did the Python designers decide that subclasses' __init__() methods don't automatically call the __init__() methods of their superclasses, as in some other languages? Is the Pythonic and recommended idiom really like the following? class Superclass(object): def __init__(self): print 'Do something' class Subclass(Superclass): def __init__(self): super(Subclass, self).__init__() print 'Do something else' The crucial distinction between Python's __init__ and those other languages constructors is that __init__ is not a constructor: it's an initializer (the actual constructor (if any, but, see

The following use of super() raises a TypeError: why? >>> from HTMLParser import HTMLParser >>> class TextParser(HTMLParser): ... def __init__(self): ... super(TextParser, self).__init__() ... self.all_data = [] ... >>> TextParser() (...) TypeError: must be type, not classobj There is a similar question on StackOverflow: Python super() raises TypeError , where the error is explained by the fact that the user class is not a new-style class. However, the class above is a new-style class, as it inherits from object : >>> isinstance(HTMLParser(), object) True What am I missing? How can I use super

I have these 4 java clases: 1 public class Rect { double width; double height; String color; public Rect( ) { width=0; height=0; color="transparent"; } public Rect( double w,double h) { width=w; height=h; color="transparent"; } double area() { return width*height; } } 2 public class PRect extends Rect{ double depth; public PRect(double w, double h ,double d) { width=w; height=h; depth=d; } double area() { return width*height*depth; } } 3 public class CRect extends Rect{ String color; public CRect(double w, double h ,String c) { width=w; height=h; color=c; } double area() { return width*height;