1. File f = new File("MyData.txt");
2. Scanner in = new Scanner(f);
3. PrintWriter out = new PrintWriter(f);

double sum = 0.0;
while (in.hasNextDouble()) {
    double n = in.nextDouble();
    sum += n;
}

1. OK
2. OK
3. Error
4. OK

try {
    PrintWriter out = new PrintWriter(new File("MyOutput.txt"));
    out.println("This is my output file.");
    out.close();
} catch (FileNotFoundException fnf) {
    System.err.println("Could not open file.");
}

public class Thingy implements Comparable<Thingy>
{
    private int value;

    public Thingy(int v)
    {
        value = v;
    }
    public int getValue()
    {
        return value;
    }

    public int compareTo(Thingy that) {
        return this.value - that.value;
    }

}

public static void cheer(int n)

{

    if (n < 0)

    {
        throw new IllegalArgumentException
        System.err.println("No negatives allowed");

        System.exit(1);
    
    }

    for (int i = 1; i <= n; i++)

    {

        System.out.println("Hip-");

    }

    System.out.println("Hooray!");

}

public interface Usable {
    public void showValues();
    public boolean hasZeroValue();
    public int getZeroLocation();
    public double solve(int zero);
}

• d) public void method() throws MyException
• e) (all of the above)
• j) if (m instanceof Circle)
• a) File