Exercise.java

package com.booleanuk.core;

public class Exercise {
    // The block of code below is a method definition. So far, you've been using methods created by other people
    // such as .length() and .charAt(n)
    // From this exercise on, you'll be writing code inside methods very often! Methods are a container for a specific
    // piece of logic that the class can run. For now, just implement your solutions between the comments that look like:
    // WRITE YOUR CODE BETWEEN THIS LINE...
    // ... AND THIS LINE
    // See the example method below
    public void example() {
        // 0. Print the word "Hello"
        // WRITE YOUR CODE BETWEEN THIS LINE...
        System.out.println("Hello");
        // ... AND THIS LINE
    }

    public int[] one() {
        int[] numbers = {42, 13, 17, 91};

        // 1. Values contained in an array are each stored at a unique numeric index, starting from 0 ascending in order.
        // E.g. The first value is at index 0, the second at index 1, the third at index 3.
        // Using an index, change the number 17 in the numbers array to 68
        // WRITE YOUR CODE BETWEEN THIS LINE...

        numbers [2] = 68;


        // ... AND THIS LINE

        return numbers;
    }

    public String two() {
        String[] teachers = {"Nathan", "Ed", "Dave", "Carlo", "Lewis", "Jules", "John", "Chris"};

        // 2. Using an array index, change the value of the teacher variable below to be the fourth
        // teacher contained in the teachers array
        // WRITE YOUR CODE BETWEEN THIS LINE...

        String teacher = "Carlo";

        teachers[3] = teacher;

        // ... AND THIS LINE

        return teacher;
    }

    public String[] three() {
        // 3. Create a string array named cars that contains three names of car manufacturers: Audi, BMW and Dodge
        // WRITE YOUR CODE BETWEEN THIS LINE...

        String[] car = {"Audi", "BMW", "Dodge"};

        // ... AND THIS LINE

        // Then change the code below to remove the dummyArray completely and return the cars array you created above instead.
        String[] dummyArray = {};
        return car;
    }

    public int four() {
        int[] numbers = {42, 13, 17, 91};

        // 4. Using array indices, set the value of the result variable below to the
        // sum of every number in the numbers array
        // WRITE YOUR CODE BETWEEN THIS LINE...
        int result = 0;
        for (int i = 0; i < 4; i++) {
            result += numbers[i];
        }

        // ... AND THIS LINE

        return result;
    }

    public float[] five() {
        // 5. Create an array called floats that contains 3 floating point numbers: 9.62, 23.17 and 3.14
        // WRITE YOUR CODE BETWEEN THIS LINE...
        float[] floats = {9.62F, 23.17F, 3.14F};


        // ... AND THIS LINE

        // Then change the code below to remove the dummyArray completely and return the floats array you created instead
        float[] dummyArray = {};
        return floats;
    }
}