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

What will this program output when run? Write down your guess and then try running it.

public class Main {
    public static void main(String[] args) {
        int x = 5;
        int y = 8;
        System.out.println(x + y);
    }
}

Challenge 2

What will this program output when run? Write down your guess and then try running it.

public class Main {
    public static void main(String[] args) {
        int x = 5;
        x--;
        x--;
        x = x + x;
        System.out.println(x);
    }
}

Challenge 3

Make it so that this program correctly determines if the numbers are even or not.

Assume that the values of x, y, and z could be changed. Don't just write out literally true and false for their current values.

public class Main {
    public static void main(String[] args) {
        int x = 5;
        int y = 4;
        int z = 98;

        boolean xIsEven = < CODE HERE >;
        System.out.println(xIsEven);

        boolean yIsEven = < CODE HERE >;
        System.out.println(yIsEven);

        boolean zIsEven = < CODE HERE >;
        System.out.println(zIsEven);
    }
}

Challenge 4

Try dividing a number by zero. What happens?

Write down your guess and then try running the program below to see.

public class Main {
    public static void main(String[] args) {
        System.out.println(5 / 0);
    }
}

Challenge 5

What can you write in the spot marked that will make the program output 2?

public class Main {
    public static void main(String[] args) {
        int x = 5;
        int y = <CODE HERE>;
        System.out.println(x + y);
    }
}

Challenge 6

What is the output of this code.¹

public class Main {
    public static void main(String[] args) {
        System.out.println(
            6 / 2 * (1 + 2)
        );
    }
}