GROUNDWORK
Chapter 4 - Making Decisions

Name: ________________________________     Date: ______________

Fill in every blank. Where a term is asked for, write the word the course
uses. Where code is asked for, write exact Java. Where output is asked
for, write what the program prints, one line per line.


VOCABULARY
----------

 1. A __________________ is an expression, written in parentheses after
    the if keyword, that produces true or false.

 2. The statements between a { and its }, which run only when the
    condition is true, are called a __________________.

 3. __________________ (two words) lets you chain more than two
    possibilities together in one decision.

 4. In Java a condition must produce a __________________ value, true or
    false, which is why if (name) is a compile error when name is a
    String.


READING CODE
------------

 5. What does this print?

        int score = 85;
        String grade;

        if (score >= 90) {
            grade = "A";
        } else if (score >= 80) {
            grade = "B";
        } else if (score >= 70) {
            grade = "C";
        } else if (score >= 60) {
            grade = "D";
        } else {
            grade = "F";
        }

        IO.println("Score " + score + " earns a " + grade + ".");

    ____________________________________

 6. What does this print?

        int score = 95;
        String grade;

        if (score >= 60) {
            grade = "D";
        } else if (score >= 70) {
            grade = "C";
        } else if (score >= 90) {
            grade = "A";
        } else {
            grade = "F";
        }

        IO.println(grade);

    ____________________________________

 7. What does this print?

        String name = "";

        if (!name.isEmpty()) {
            IO.println("Hello, " + name + ".");
        } else {
            IO.println("Hello, stranger.");
        }

    ____________________________________

 8. What does this print?

        boolean hasTicket = false;
        int age = 20;

        if (hasTicket) {
            if (age >= 13) {
                IO.println("Enjoy the show.");
            } else {
                IO.println("You need an adult with you.");
            }
        } else {
            IO.println("Please buy a ticket first.");
        }

    ____________________________________

 9. What does this print?

        int score = 45;

        if (score >= 60)
            IO.println("You passed.");
            IO.println("Congratulations.");

    ____________________________________


WRITING CODE
------------

10. Complete this line so the age the user types is read as a whole
    number:
    int age = __________________(IO.readln("Your age: ").strip());

11. Complete the catch so it handles the exception Integer.parseInt
    throws when it cannot read the text:
    try {
        int tickets = Integer.parseInt(answer.strip());
        IO.println("That will be $" + (tickets * 12) + ".");
    } catch (__________________ e) {
        IO.println("Please enter a whole number.");
    }

12. Complete this program so a price that is not a number is caught:
    __________________ {
        double price = Double.parseDouble(answer.strip());
        IO.println("With tax: $" + String.format("%.2f", price * 1.08));
    } catch (NumberFormatException e) {
        IO.println("That is not a number.");
    }

13. Complete this condition so the Tuesday discount applies only when
    the price is greater than 0, never to a free ticket:
    int discount = 0;
    if (day.equals("tuesday") && price __________________ 0) {
        discount = 3;
        price -= discount;
    }


WHY IT WORKS
------------

14. Java checks else if conditions in the order they are written and
    stops at the first one that is __________________, which is why a
    score of 95 in the reordered chain gets the grade "__________________"
    instead of "A".

15. The ticket program puts Integer.parseInt inside a try because, given
    text such as three, it throws a NumberFormatException that would
    otherwise __________________.

16. name.isEmpty() gives back __________________ for the empty string "",
    which is why !name.isEmpty() is false and the program prints "Hello,
    stranger." when the user presses Enter without typing anything.