Constructor Chain

Lab Java Intermediate 20 points

Create A, B extends A and C extends B, each printing A(), B(), C() in its constructor. Read a letter and create that object, printing the constructors in the order they run, then done.

Input

One letter: A, B or C.

Output

The constructor messages, then done.

Example

Input

Output

A()
B()
C()
done

Sample input available Sample output available

Editor

Java

Hints

Every constructor first calls its parent's constructor (implicitly super()).

Solution explanation

Objects are built from the top of the hierarchy down, so parents are ready before children.

Show solution

import java.util.Scanner;

class A {
    A() {
        System.out.println("A()");
    }
}

class B extends A {
    B() {
        System.out.println("B()");
    }
}

class C extends B {
    C() {
        System.out.println("C()");
    }
}

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String which = sc.next();
        if (which.equals("A")) {
            new A();
        } else if (which.equals("B")) {
            new B();
        } else {
            new C();
        }
        System.out.println("done");
    }
}

Output

Answer