Herman Gard Stornes

src/main/java/com/booleanuk/core/Exercise.java

@@ -3,31 +3,37 @@
 import com.booleanuk.helpers.ExerciseBase;
 
 import java.util.ArrayList;
+import java.util.List;
+import java.util.stream.Collectors;
 
 public class Exercise extends ExerciseBase {
     /*
-        A List is like an array but provides a much easier interface to the items it stores, for example:
-        - A list doesn't need to have a predefined size, we can add and remove as many things as memory allows
-        - We can more easily run looping operations on lists
-        - A list is an interface that has multiple implementations depending on the data structure we want,
-        e.g. ArrayList, LinkedList, Stack
-        - This exercise will focus on using the ArrayList
+     * A List is like an array but provides a much easier interface to the items it
+     * stores, for example:
+     * - A list doesn't need to have a predefined size, we can add and remove as
+     * many things as memory allows
+     * - We can more easily run looping operations on lists
+     * - A list is an interface that has multiple implementations depending on the
+     * data structure we want, e.g. ArrayList, LinkedList, Stack
+     * - This exercise will focus on using the ArrayList
      */
 
     /*
-        Take some time to read and understand the method below.
-        - It creates an instance of an ArrayList that will contain Integer types
-            We define the data type that will be stored in a list using angled brackets:
-            ArrayList<Datatype>
-            We can store any data type in a list, even our own custom classes.
-            ArrayList<String>
-            ArrayList<Boolean>
-            ArrayList<Exercise>
-
-        - It adds a few numbers to the list
-        - It outputs the list that now contains a few numbers
-
-        Documentation: https://docs.oracle.com/en/java/javase/18/docs/api/java.base/java/util/ArrayList.html
+     * Take some time to read and understand the method below.
+     * - It creates an instance of an ArrayList that will contain Integer types
+     * We define the data type that will be stored in a list using angled brackets:
+     * ArrayList<Datatype> We can store any data type in a list, even our own custom
+     * classes.
+     * ArrayList<String>
+     * ArrayList<Boolean>
+     * ArrayList<Exercise>
+     * 
+     * - It adds a few numbers to the list
+     * - It outputs the list that now contains a few numbers
+     * 
+     * Documentation:
+     * https://docs.oracle.com/en/java/javase/18/docs/api/java.base/java/util/
+     * ArrayList.html
      */
     public ArrayList<Integer> getFavouriteNumbers() {
         ArrayList<Integer> list = new ArrayList<>();
@@ -40,57 +46,76 @@ public ArrayList<Integer> getFavouriteNumbers() {
     }
 
     /*
-        TODO: 1. Create a method named getSecondNumber that returns a whole number. It must return the
-           second number contained in the list that is returned from getFavouriteNumbers
+     * TODO: 1. Create a method named getSecondNumber that returns a whole number.
+     * It must return the
+     * second number contained in the list that is returned from getFavouriteNumbers
      */
-
-
+    public int getSecondNumber() {
+        return this.getFavouriteNumbers().get(1);
+    }
 
     /*
-        TODO: 2. Create a method named multiply that accepts two parameters in this order:
-         - A list of whole numbers
-         - A whole number
-         The method must multiply each number in the provided list by the number provided in the second
-         parameter, and then return the updated list.
-         Use the ArrayList's replaceAll method to iterate through the ArrayList and replace each value with its double
-         https://www.programiz.com/java-programming/library/arraylist/replaceall
+     * TODO: 2. Create a method named multiply that accepts two parameters in this
+     * order:
+     * - A list of whole numbers
+     * - A whole number
+     * The method must multiply each number in the provided list by the number
+     * provided in the second
+     * parameter, and then return the updated list.
+     * Use the ArrayList's replaceAll method to iterate through the ArrayList and
+     * replace each value with its double
+     * https://www.programiz.com/java-programming/library/arraylist/replaceall
      */
-
-
+    public ArrayList<Integer> multiply(ArrayList<Integer> list, int factor) {
+        // Just doing it this way for fun, even if its not the recommended way
+        return list.stream().map(x -> x * factor).collect(Collectors.toCollection(ArrayList::new));
+    }
 
     /*
-        TODO: 3. Create a method named isEmpty that accepts one parameter:
-         - A list of strings
-         The method must return a boolean that indicates whether the provided list is empty or not
+     * TODO: 3. Create a method named isEmpty that accepts one parameter:
+     * - A list of strings
+     * The method must return a boolean that indicates whether the provided list is
+     * empty or not
      */
-
-
+    public boolean isEmpty(ArrayList<String> strings) {
+        return strings.isEmpty();
+    }
 
     /*
-        TODO: 4. Create a method named addIngredient that accepts two parameters in this order:
-         - A list of strings
-         - A string
-         The method must add the second parameter into the list provided and then return the list
+     * TODO: 4. Create a method named addIngredient that accepts two parameters in
+     * this order:
+     * - A list of strings
+     * - A string
+     * The method must add the second parameter into the list provided and then
+     * return the list
      */
-
-
+    public ArrayList<String> addIngredient(ArrayList<String> ingredients, String ingredient) {
+        ingredients.add(ingredient);
+        return ingredients;
+    }
 
     /*
-        TODO: 5. Create a method named removeIngredient that accepts two parameters in this order:
-         - A list of strings
-         - A string
-         The method must remove the second parameter from the list and then return the list
+     * TODO: 5. Create a method named removeIngredient that accepts two parameters
+     * in this order:
+     * - A list of strings
+     * - A string
+     * The method must remove the second parameter from the list and then return the
+     * list
      */
-
-
+    public ArrayList<String> removeIngredient(ArrayList<String> ingredients, String ingredient) {
+        ingredients.remove(ingredient);
+        return ingredients;
+    }
 
     /*
-        TODO: 6. Create a method named containsIngredient that accepts two parameters in this order:
-         - A list of strings
-         - A string
-         The method must return a boolean that indicates whether the second parameter exists in the provided list
+     * TODO: 6. Create a method named containsIngredient that accepts two parameters
+     * in this order:
+     * - A list of strings
+     * - A string
+     * The method must return a boolean that indicates whether the second parameter
+     * exists in the provided list
      */
-
-
-
+    public boolean containsIngredient(ArrayList<String> ingredients, String ingredient) {
+        return ingredients.contains(ingredient);
+    }
 }