overriding

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: Howto change what Default(T) returns in C# print(default(int) == 0) //true Similarly if I have a custom object, its default value will be null. print(default(Foo) == null) //true Can I have a custom value for default(Foo) and not null? For example, something like this: public static override Foo default() { return new Foo(); } This wont compile. Thanks.. 回答1: You can't override the default(T) keyword. It is

问题 I have tried to override val in Scala as this: trait T{ val str: String } sealed abstract class Test extends T{ val str: String = "str" } class Test1 extends Test{ val str = super.str + "test1" //super may not be used on value str } But this refused to compile. Why? I wanted to override value in the abstract class using the abstract class's value itself. How to do this? In my particular case I cannot pass it as a class parameter. 回答1: Scala compiler does not allow to use super on a val . If

问题 Is it possible to create a wrapper around a function that has the exact same name as the original function? This would be very useful in circumstances where the user wants to do some additional checks on input variables before they are passed on to the built in function How to interrupt MATLAB IDE when it hangs on displaying very large array? 回答1: Actually alternatively to slayton's answer you don't need to use openvar . If you define a function with the same name as a matlab function, it

问题 Given a class A and a module B, mixin the instance methods of B so that it overrides the correspnding instance methods of A. module B def method1 "B\#method1" end def method2 "B\#method2" end end class A def method1 "A\#method1" end def method2 "A\#method2" end # include B does not override instance methods! # (module gets mixed into the superclass) end puts A.new.method1 # want it to print out "B#method1" puts A.new.method2 # want it to print out "B#method2" 回答1: You could remove each of B

问题 First off, let me say I am pretty new to coding in general, so please be specific in your responses =) I am having an issue with borders around images on a site I am working on. You can see the site here: http://eventswithvizability.ca/ I have 10 images rotating on page reload, you can see the HTML here: <SCRIPT LANGUAGE="Javascript"> function banner() { } ; b = new banner() ; n = 0 b[n++]= "<IMG name=randimg CLASS='aligncenter1'>" b[n++]= "<IMG name=randimg CLASS='aligncenter2'>" b[n++]= "

问题 I use the following CSS to apply a top border to the last-child row of various tables: .mytabs tr:last-child { border-top:1px solid #000; font-weight:bold;} Now what I need to do is to override this style for one particular table. How can I override this style in one specific instance? Thanks. 回答1: You can wrap it a custom div id name example <div id="customFormat"></div> or give the table an id <table id="customFormat"></table> In CSS, you can specify the custom styling just for that 1 table

问题 I know how to call a method in a super class from a subclass by super. even when the method is overriden. But how can I call the method in the super class? Is it impossible? public class Test extends Super{ public static void main (String[] args){ Test t = new Test(); t.print(); } void print1(){ System.out.println("Hello"); } } class Super{ void print1(){ System.out.println("hi"); } void print(){ print1(); // What can I do when I want to print "hi" } } 回答1: Once you override a function, the

问题 I hope this is a simple question. I need to intercept didAddSubview , but will I need to subclass the UIView in order to override that method? The UIView that I want to override is the UIViewController 's view property, so I just want to know how to go about working with this. Thanks! 回答1: From Apple UIView documentation (see Methods to Override ): When subclassing UIView, there are only a handful of methods you should override and many methods that you might override depending on your needs.

问题 Here is my code class Glyph { void draw() { System.out.println("Glyph.draw()"); } Glyph(int i) { System.out.println("Glyph() before draw()"); draw(); System.out.println("Glyph() after draw()"); } } class RoundGlyph extends Glyph { private int radius = 1; RoundGlyph(int r) { super(r); radius = r; System.out.println("RoundGlyph.RoundGlyph(), radius = " + radius); } void draw() { System.out.println("RoundGlyph.draw(), radius = " + radius); } } public class PolyConstructors { public static void

问题 Here is my code class Glyph { void draw() { System.out.println("Glyph.draw()"); } Glyph(int i) { System.out.println("Glyph() before draw()"); draw(); System.out.println("Glyph() after draw()"); } } class RoundGlyph extends Glyph { private int radius = 1; RoundGlyph(int r) { super(r); radius = r; System.out.println("RoundGlyph.RoundGlyph(), radius = " + radius); } void draw() { System.out.println("RoundGlyph.draw(), radius = " + radius); } } public class PolyConstructors { public static void