Tags | technical-assessment skill/classes_and_objects |
On Tilde you will notice that this card is asking for a link submission. Please don’t worry about submitting a link. You will be assessed according to TOPIC: Introduction to live assessments
You need to prove that you understand the following concepts:
The constructor is a method that is called when an object is created. This method is defined in the class and can be used to initialize basic variables. In Python the __init__()
method is called in place of the constructor - to instantiate (initialise) the object.
class Rectangle:
def __init__(self, length, width):
...
The learner should know how to create an initialiser that takes in arguments and create instance variables.
The learner should be able to instantiate the object.
rectangle = Rectangle(2,4)
The learner should also understand how multiple instances of an object work.
small_rectangle1 = Rectangle(2, 4)
small_rectangle2 = Rectangle(2, 4)
medium_rectangle = Rectangle(4, 12)
The learner should know what is inheritance and what it means when a class inherits another class. Both single and multiple inheritances should be understood, and the use of super()
in both cases.
class Square(Rectangle):
pass
class Cuboid(Rectangle):
def __init__(self, length, width, height):
super().__init__(length, width)
self.height = height
The learner should know how to override a function using super and without using super.
The learner should know that the constructor name must be the same as its class name.
class Rectangle{
Rectangle(){
....
}
The learner should know that a single class can have multiple constructors with different numbers of parameters.
class Rectangle{
....
// no arg constructor
Rectangle()
....
// parameterized constructor
Rectangle(double length, double width)
....
The learner should know how to instantiate a class object.
Rectangle rectangle1 = new Rectangle();
Rectangle rectangle2 = new Rectangle(10.0, 6.0);
Rectangle rectangle2 = new Rectangle(6.0, 7.0);
The learner must know that to inherit from a class, the keyword extends is used.
class Square extends Rectangle { .... }
class Cuboid extends Rectangle {
private double length, width, height;
public Cuboid(double length, double width, double height) {
super(length, width);
this.length = height;
}
....
}
Learner should know that constructors and methods declared with final or static cannot be overridden. If a method cannot be inherited, it cannot be overridden.
Learner should know how constructors work
class Rectangle {
constructor(length, width){
this.length = length
this.width = width
}
}
Learner should know how to instantiate many objects from the same class and interact with them
const smallRectangle1 = new Rectangle(2, 4)
const smallRectangle2 = new Rectangle(2, 4)
const mediumRectangle = new Rectangle(4, 12)
console.log(smallRectangle1.length) //2
console.log(mediumRectangle.width) //12
Learner should understand inheritance and overriding and extending methods
class Rectangle {
...
details(){
return `The length of the rectangle is ${this.length}, and the width is ${this.width}`;
}
}
class Cuboid extends Rectangle {
constructor(length, width){
super();
};
details(){
return `The length of the cuboid is ${this.length}, and the width is ${this.width}`;
};
};
The learner should know that constructors and methods declared with final or static cannot be overridden. If a method cannot be inherited, it cannot be overridden.