Quiz 12 Solution

1. Suppose you are given the class Youngster, which represents a young
person with a name and an age. Complete the methods of the class
Teenager, which is a subclass of Youngster, and in addition to name and
age also stores a summer job. Be sure to avoid repetitive code. [4 marks]

class Youngster {
    private String name; // this Youngster's name
    private int age; // this Youngster's age, in years

    // Constructor: initializes this Youngster's name and age
    // to 'n' respectively 'a'
    public Youngster (String n, int a) {
        name = n;
        age = a;
    }

    // Returns the information about this Youngster
    public String getInfo() {
        return "Name: " + name + "\t" + "Age: " + age;
    }
}

/**
 * Represents a teenager, who, in addition
 * to a name and an age, also has a summer job.
 */
class Teenager extends Youngster {
    private String summerJob;

    // Constructor: initializes this Teenager's name, age, and summer job
    // respectively to 'n', 'a', and 's'
    public Teenager (String n, int a, String s) {
        super (n, a);
        summerJob = s;
    }

    // Returns the name, age, and summer job of this Teenager
    // Format: similar to the Youngster (i.e. each piece of info
    // is labelled and separated from the one before it by a "\t")
    public String getInfo ( ) {
        return super.getInfo() + "\t" + "Summer Job: " + summerJob;
    }

    // Returns the summer job of this teenager
    public String getJob() {
        return summerJob;
    } 
}

2. 

a) In the main method below, there are 2 lines that cause compilation
    errors. Circle them. [3 marks]

b) If these lines were removed from the program, what would be its
    output? Write it in the box below. [3 marks]

class Quiz {
    public static void main (String[] args) {
        Youngster y1 = new Youngster("Alice", 10);
        Teenager t1 = new Teenager ("Jim", 14, "Sales Clerk");

        Youngster y2 = new Teenager ("Daniel", 16, "Office Gopher");
        Teenager t2 = new Youngster ("Michaela", 15); //constructor protests

        System.out.println (y1.getInfo()); 
        System.out.println (y2.getInfo()); 
 
        System.out.println (t1.getJob()); 
        System.out.println (y2.getJob()); //needs a cast 
    } 
}

OUTPUT

   Name: Alice Age: 10
   Name: Daniel Age: 16 Summer Job: Office Gopher
   Sales Clerk