Constructor Inheritance

If there is a constructor in the parent class, the daughter class will inherit it. Here you create square, but use a Rectangle constructor, so you should pass both height and width parameters.


              12
            
rectangle = new Rectangle(2, 5);
square = new Square(4, 4);

This is a bit inconvenient, so let's create constructor for Square class, that will use Rectangle constructor. To do that in daughter class, you should use super() function to call the parent constructor first.


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class Rectangle {
  height;
  width;
  constructor(height, width) {
    this.height = height;
    this.width = width;
    console.log('Rectangle created');
  }
}

class Square extends Rectangle{
  constructor(size){
    super(size, size);
    // init other attributes if it is required
    console.log('Square created');
  }
}

square = new Square(5);

This way, first you call Rectangle's constructor(height, width), and after define other attributes initialization. Then Square`s constructor is called. This way, first you create parent's object, and after that daughter's one.

Tehtävä

Swipe to start coding

To the class Square, add attribute color. Then create constructor with two parameters: side length and color. In its body, call Rectangle constructor to initialize width and length, and then initialize color.

Ratkaisu

Vaihda työpöytään todellista harjoitusta vartenJatka siitä, missä olet käyttämällä jotakin alla olevista vaihtoehdoista

Oliko kaikki selvää?

Kiitos palautteestasi!

Osio 4. Luku 2

Constructor Inheritance

If there is a constructor in the parent class, the daughter class will inherit it. Here you create square, but use a Rectangle constructor, so you should pass both height and width parameters.


              12
            
rectangle = new Rectangle(2, 5);
square = new Square(4, 4);


              12345678910111213141516171819
            
class Rectangle {
  height;
  width;
  constructor(height, width) {
    this.height = height;
    this.width = width;
    console.log('Rectangle created');
  }
}

class Square extends Rectangle{
  constructor(size){
    super(size, size);
    // init other attributes if it is required
    console.log('Square created');
  }
}

square = new Square(5);

Tehtävä

Swipe to start coding

Ratkaisu

Vaihda työpöytään todellista harjoitusta vartenJatka siitä, missä olet käyttämällä jotakin alla olevista vaihtoehdoista

Oliko kaikki selvää?

Kiitos palautteestasi!

Osio 4. Luku 2

Vaihda työpöytään todellista harjoitusta vartenJatka siitä, missä olet käyttämällä jotakin alla olevista vaihtoehdoista