:
class Test{}
object Driver extends Test{
}
:
abstract Fruit{
val name :String
val color :String
}
object Fruit{
object Apple extends Fruit("apple","red")
val menu=List(Apple)
}
question:
(1) Why object in scala can also inherit from class or trait using extends. How to understand
(2) Why does extens Fruit ("A", "B") take two parameters here in the second paragraph of code?
Thank you for answering questions!
add:
object can extend a class or trait, and the result is an object that extends the specified class or trait and has all the features given in the object definition. The difference between object and class is that you can understand that object is a singleton pattern, which can only have one, while class can create more than one. abstract Fruit ? And the code blocks are enclosed in large brackets, and the two values in Fruit are both val . You must use the main constructor method instead of parentheses. The following can be compiled:
The object in - scala is not a simple concept of an object, it can also be seen as a class. Similar to the tool class in java. You can inherit other classes.
- inherits the Fruit class, setting name and color. whenever you instantiate an object with Apple Then initializing during inheritance avoids the problem of initializing properties each time when Apple is instantiated multiple times.
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