Overloading is defining functions that have similar signatures, yet have different parameters. Overriding is only pertinent to derived classes, where the parent class has defined a method and the derived class wishes to override that method. In PHP, you can only overload methods using the magic method __call. An example of overriding: <?php class Foo … Read more
Definitely a matter of style. I prefer constructors with default parameters, so long as the parameters make sense. Classes in the standard use them as well, which speaks in their favor. One thing to watch out for is if you have defaults for all but one parameter, your class can be implicitly converted from that … Read more
Polymorphism 1. Static binding/Compile-Time binding/Early binding/Method overloading.(in same class) 2. Dynamic binding/Run-Time binding/Late binding/Method overriding.(in different classes) overloading example: class Calculation { void sum(int a,int b){System.out.println(a+b);} void sum(int a,int b,int c){System.out.println(a+b+c);} public static void main(String args[]) { Calculation obj=new Calculation(); obj.sum(10,10,10); // 30 obj.sum(20,20); //40 } } overriding example: class Animal { public void move(){ … Read more
Java will always try to use the most specific applicable version of a method that’s available (see JLS §15.12.2). Object, char[] and Integer can all take null as a valid value. Therefore all 3 version are applicable, so Java will have to find the most specific one. Since Object is the super-type of char[], the … Read more
Use object.ReferenceEquals(person1, null) or the new is operator instead of the == operator: public static bool operator ==(Person person1, Person person2) { if (person1 is null) { return person2 is null; } return person1.Equals(person2); }
I’d like to cite Lukas Rytz (from here): The reason is that we wanted a deterministic naming-scheme for the generated methods which return default arguments. If you write def f(a: Int = 1) the compiler generates def f$default$1 = 1 If you have two overloads with defaults on the same parameter position, we would need … Read more
Java always calls the method that best suits your argument. Auto boxing and implicit upcasting is only performed if there’s no method which can be called without casting / auto boxing. The List interface specifies two remove methods (please note the naming of the arguments): remove(Object o) remove(int index) That means that list.remove(1) removes the … Read more
You cannot overload PHP functions. Function signatures are based only on their names and do not include argument lists, so you cannot have two functions with the same name. Class method overloading is different in PHP than in many other languages. PHP uses the same word but it describes a different pattern. You can, however, … Read more
It’s method overloading, not method overriding. And in Python, you historically do it all in one function: class A: def stackoverflow(self, i=’some_default_value’): print ‘only method’ ob=A() ob.stackoverflow(2) ob.stackoverflow() See the Default Argument Values section of the Python tutorial. See “Least Astonishment” and the Mutable Default Argument for a common mistake to avoid. See PEP 443 … Read more
From the Java Language Specification, section 15.9.5.1: An anonymous class cannot have an explicitly declared constructor. Sorry 🙁 EDIT: As an alternative, you can create some final local variables, and/or include an instance initializer in the anonymous class. For example: public class Test { public static void main(String[] args) throws Exception { final int fakeConstructorArg … Read more