constructor

问题 This question already has answers here : How do I call New-Object for a constructor which takes a single array parameter? (2 answers) Closed 2 years ago . It seems that there is a bug in the O-O support in PowerShell . When instantiating an object of a class with a constructor that accepts a List< T > and this is the only parameter , PowerShell cannot find a proper constructor. Code sample: class MyClass { MyClass( #[int]$i, [System.Collections.Generic.List[string]] $theparams) { } }

问题 This question already has answers here : How do I call New-Object for a constructor which takes a single array parameter? (2 answers) Closed 2 years ago . It seems that there is a bug in the O-O support in PowerShell . When instantiating an object of a class with a constructor that accepts a List< T > and this is the only parameter , PowerShell cannot find a proper constructor. Code sample: class MyClass { MyClass( #[int]$i, [System.Collections.Generic.List[string]] $theparams) { } }

问题 Is it mandatory to call the parent's constructor from the constructor in the child class constructor? To explain consider the following example: class Parent{ function __construct(){ //something is done here. } } class Child extends Parent{ function __construct(){ parent::__construct(); //do something here. } } This is quite normal to do it as above. But consider the following constructors of the class Child : function __construct(){ //Do something here parent::__construct(); } Is the above

问题 I was looking through the PHP documentation and saw several comments where a variable was initialized outside of a class's constructor, similar to the following: classMyClass { private $count = 0; public function __construct() { //Do stuff } } In PHP Objects, Patterns, and Practice , the author recommends using constructs only for the initialization of properties, deferring any heavy lifting or complex logic to specialized methods. This tutorial (a quick example that I found on Google) also

问题 I was looking through the PHP documentation and saw several comments where a variable was initialized outside of a class's constructor, similar to the following: classMyClass { private $count = 0; public function __construct() { //Do stuff } } In PHP Objects, Patterns, and Practice , the author recommends using constructs only for the initialization of properties, deferring any heavy lifting or complex logic to specialized methods. This tutorial (a quick example that I found on Google) also

问题 I was looking through the PHP documentation and saw several comments where a variable was initialized outside of a class's constructor, similar to the following: classMyClass { private $count = 0; public function __construct() { //Do stuff } } In PHP Objects, Patterns, and Practice , the author recommends using constructs only for the initialization of properties, deferring any heavy lifting or complex logic to specialized methods. This tutorial (a quick example that I found on Google) also

问题 I was looking through the PHP documentation and saw several comments where a variable was initialized outside of a class's constructor, similar to the following: classMyClass { private $count = 0; public function __construct() { //Do stuff } } In PHP Objects, Patterns, and Practice , the author recommends using constructs only for the initialization of properties, deferring any heavy lifting or complex logic to specialized methods. This tutorial (a quick example that I found on Google) also

问题 In the following example: class Base { int x=10; Base() { show(); } void show() { System.out.print ("Base Show " +x + " "); } } class Child extends Base { int x=20; Child() { show(); } void show() { System.out.print("Child Show " + x +" ") ; } public static void main( String s[ ] ) { Base obj = new Child(); } } Why is the output as shown below Child Show 0 Child Show 20 I thought constructors can only access instance members once its super constructors have completed. I think what is

问题 Here's the definition of copy constructor, [class.copy.ctor/1]: A non-template constructor for class X is a copy constructor if its first parameter is of type X&, const X&, volatile X& or const volatile X&, and either there are no other parameters or else all other parameters have default arguments ([dcl.fct.default]). Why does the standard exclude templates as copy constructors? In this simple example, both constructors are copy constructors: struct Foo { Foo(const Foo &); // copy

问题 public Module(string a, object obj) : this(a, null, obj) { } public Module(string b, object obj) : this(null, b, obj) { } These constructor overloads do not work 'already defines a member with same parameter types' I have looked around and realise that I cannot do this in c# but can anyone suggest a way around this? Edit: Thanks for answers. In this case I have decided that to go with this for now: public Module(string a, object obj) : this(a, null, obj) { } public Module(string a, string b,