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Instantiate subclass without constructing


Instantiate subclass without constructing

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Instantiate subclass without constructing
Tag : javascript , By : Thx1138.6
Date : January 12 2021, 01:40 AM

I wish this helpful for you I would use an initialization function separate from the constructor as that give you more control over when/if parent initialization happens.
class Parent {
  constructor(x) {
    this.init(x);
    console.log("parent constructor does other stuff");
  }
  init(x) {
    console.log("parent init runs")
  }
}

class Child extends Parent {
  constructor(x) {
    super(x);
  }

  init(x) {
    console.log("child init runs");
    super.init(x); // This call is optional if you don't want to run the parent's init code
  }
}

let c = new Child();

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How does this subclass instantiate itself?


Tag : objective-c , By : B3CFT
Date : March 29 2020, 07:55 AM
Hope this helps When you call [super something], you are using the superclass's implementation of the method, but the method is still called on the same object that the current method is called on. In other words, the self in the super call is the same as the self in the current function -- the PKAnimation class (or whatever class you called this method on).
This depends on knowing that +[CABasicAnimation animationWithKeyPath:] creates an object of the class that it's called on. But this is a convention that is followed by all convenience constructors in Cocoa. They always create the object using [self alloc] ... rather than [SomeSpecificClass alloc] ..., therefore, it will always use the class object that the method (which may be inherited) is called on at runtime, not the class that the code is physically in at compile time.

Constructing a Subclass Object in a Completely Different Class


Tag : java , By : browe
Date : March 29 2020, 07:55 AM
I wish this help you As @tsnorri mentioned in comment, you should simply declare Rectas class out of Shapeone.
public class Shape {

}

public class Rect extends Shape {
    //rect instance variables
    public Rect(){
        super();
        System.out.print("Youve made a rect within shape");
    }
}
import java.util.ArrayList;

class ImageMaker
{
    static ArrayList<Shape> shapes = new ArrayList<Shape>();//all the shapes contained in the image

    public static void main(String args[])
    {
        shapes.add(new Shape());
        shapes.add(new Rect());
    }

    public static class Shape {
        System.out.print("Created new Shape");
    }

    public static class Rect extends Shape {
        //rect instance variables
        public Rect(){
            super();
            System.out.print("You've made a rect within shape");
        }
    }
}

What's wrong with my way of constructing an object of a subclass?


Tag : cpp , By : WuJanJai
Date : March 29 2020, 07:55 AM
I think the issue was by ths following , Here's my subclass: , I think you have
class CChildView : public CWnd
{
    // ...
    BackGround Bg1(0);                // Line 46
    BackGround Bg2(-WINDOW_HEIGHT);   // Line 47
};
class CChildView : public CWnd
{
    // ...
    BackGround Bg1 {0}; 
    BackGround Bg2 {-WINDOW_HEIGHT};
};
class CChildView : public CWnd
{
    CChildView();
    // ...
    BackGround Bg1; 
    BackGround Bg2;
};

// ... 

CChildView::CChildView() : Bg1(0), Bg2(-WINDOW_HEIGHT)
{
    // ...
}

Python: Constructing a multiple-inheritance subclass instance from a superclass


Tag : python , By : Mena
Date : March 29 2020, 07:55 AM
will be helpful for those in need Bugs are already there - when you do self.gates = circuit.gates, circuit.gates being a list, yu point both references to the same list - and if this list is updated on the original circuit, this update will be reflected in your subcircuit instance.
I think the most sane pattern tehre is to have an alternate constructor for the class if you have a circuit instance from which to update your own:
from copy import copy
class SubCircuit(Gate, Circuit):
    def __init__(self, size):
        Gate.__init__(self, size)
        Circuit.__init__(self, size)

    @classmethod
    def from_circuit(cls , circuit, size):
        self = SubCircuit(size)
        for key, value in circuit.__dict__.items():
             setattr(self, key, copy(value))
        return self

How to instantiate subclass from within a superclass


Tag : java , By : user150744
Date : March 29 2020, 07:55 AM
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