MCQ - 1 Review

int x = 7;
int y = 3;
if ((x < 10) && (y < 0)) {
    System.out.println("Value is: " + x * y);
} else {
    System.out.println("Value is: " + x / y);
}

Value is: 2

y is > 0, so the conditional fails and the code in the else block is ran. Therefore, it will print out the value 7 / 3. However, this is integer division, and therefore the resulting output is 2.

Q12: What is returned as a result of the call mystery(“computer”)

public String mystery(String input) {
    String output = "";

    for (int k = 1; k < input.length(); k = k + 2) {
        output += input.substring(k, k + 1);
    }

    return output;
}

mystery("computer");

optr

The for loop increments by two, iterating over every other element in the list and appending it to the output string.

Q19: The expression !(!(a != b) && (b > 7)) is equal to which of the following?

Simplification: !(!(a != b) && (b > 7)) !((a == b) && (b > 7)) !(a == b) || !(b > 7) (a != b) || (b <= 7)

Notes

Starting in the second half, I began using java, and it helped a lot more.

Example: Q23, best visualised with an extra print statement:

Q23: What will be the contents of animals be as a result of calling manipulate?

private List<String> animals = new ArrayList<>(Arrays.asList("bear", "zebra", "bass", "cat", "koala", "baboon"));

public void manipulate(List<String> animals) {
    for (int k = animals.size() - 1; k > 0; k--) {
        if (animals.get(k).substring(0, 1).equals("b")) {
            animals.add(animals.size() - k, animals.remove(k));
        }
        System.out.println(animals);
    }
}

manipulate(animals)

[bear, baboon, zebra, bass, cat, koala]
[bear, baboon, zebra, bass, cat, koala]
[bear, baboon, zebra, bass, cat, koala]
[bear, baboon, zebra, bass, cat, koala]
[bear, zebra, bass, cat, koala, baboon]

This is much easier to visualize than thinking through individually, although that is what will have to happen on the AP test.