Challenges

Remember the rules for this are

Try to use only the information given up to this point in this book.
Try not to give up until you've given it a solid attempt

Challenge 1.

Write a method named isSorcerer. If the method is given any of "yuji" or "gojo" return true. Otherwise return false.

Start by writing this with if and else. Then alter the code so it uses switch instead.

boolean isSorcerer(String name) {
    // CODE HERE
}

void main() {
    System.out.println(
        isSorcerer("yuji")
    );

    System.out.println(
        isSorcerer("gojo")
    );

    System.out.println(
        isSorcerer("yugi") // Wrong series
    );
}

Challenge 2.

Same basic challenge as above, but write a method named didRedSoxWin which takes an int representing a year.

Return true if that is a year the Boston Red Sox won a world series. false otherwise. This time start off by using a switch.

boolean didRedSoxWin(int year) {
    // CODE HERE
}

void main() {
    System.out.println(
        "2004: " + didRedSoxWin(2004)
    );

    System.out.println(
        "1998: " + didRedSoxWin(1998)
    );

    System.out.println(
        "2013: " + didRedSoxWin(2013)
    );

    System.out.println(
        "1903: " + didRedSoxWin(1903)
    );
}

Challenge 3.

Make a method named transition which takes in a StopLight and returns the next light it will transition to.

For those who don't drive cars: red lights go to green, green lights go to yellow, and yellow lights go to red.

This is a duplicate of a challenge from a previous section. This time do it using a switch.

enum StopLight {
    RED,
    YELLOW,
    GREEN
}

StopLight transition(StopLight current) {
    // ------------
    // CODE HERE
    // ------------
}

void main() {
    var light = StopLight.RED;
    System.out.println(light);

    light = transition(light);
    System.out.println(light);

    light = transition(light);
    System.out.println(light);

    light = transition(light);
    System.out.println(light);

    light = transition(light);
    System.out.println(light);

    light = transition(light);
    System.out.println(light);

    light = transition(light);
    System.out.println(light);
}

Challenge 4.

In reality a StopLight can also be broken and not function at all. Alter transition so it accounts for a new BROKEN state which transitions to itself. (BROKEN goes to BROKEN).

enum StopLight {
    RED,
    YELLOW,
    GREEN,
    BROKEN
}

StopLight transition(StopLight current) {
    // ------------
    // CODE HERE
    // ------------
}

void main() {
    var light = StopLight.RED;
    System.out.println(light);

    light = transition(light);
    System.out.println(light);

    light = transition(light);
    System.out.println(light);

    light = transition(light);
    System.out.println(light);

    light = transition(light);
    System.out.println(light);

    light = transition(light);
    System.out.println(light);

    light = transition(light);
    System.out.println(light);
}

Challenge 5.

Given a type of bear, return the correct course of action if you run into one in the wild and it attacks you.

If the bear is null, return null as the action to take.

If you don't know what to do when you run into a bear, look it up. Use switch first then try writing the same logic using if and else.

enum Bear {
    POLAR,
    BROWN,
    BLACK,
    PANDA,
    KOALA
}

enum Action {
    LAY_DOWN,
    FIGHT_BACK,
    RUN_AWAY
    YEET
}

Action inCaseOfBearAttack(Bear bear) {
    // CODE HERE
}

void main() {
    System.out.println(
        inCaseOfBearAttack(Bear.POLAR)
    );

    System.out.println(
        inCaseOfBearAttack(Bear.BROWN)
    );


    System.out.println(
        inCaseOfBearAttack(Bear.BLACK)
    );

    System.out.println(
        inCaseOfBearAttack(Bear.PANDA)
    );

    System.out.println(
        inCaseOfBearAttack(Bear.KOALA)
    );

    System.out.println(
        inCaseOfBearAttack(null)
    );
}

Modern Java