Chapter 19 Ex: 4 and 5

Author: HarryDulaney

ch_19/Exercise19_03.java

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+package ch_19;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+
+/**
+ * 19.3 (Distinct elements in ArrayList) Write the following method that returns a new
+ * ArrayList.
+ * <p>
+ * The new list contains the non-duplicate elements from the original list. <br>
+ * {@code public static <E> ArrayList<E> removeDuplicates(ArrayList<E> list) }
+ */
+public class Exercise19_03 {
+
+    public static void main(String[] args) {
+        //Test the method
+        ArrayList<String> testList = new ArrayList<>(Arrays.asList("party", "Tomorrow", "Friday", "cereal", "14", "real",
+                "pizza", "party", "Friday", "Thursday", "weekends", "14", "party"));
+        System.out.println(removeDuplicates(testList));
+    }
+
+    public static <E> ArrayList<E> removeDuplicates(ArrayList<E> list) {
+        if (list.size() == 0 || list.size() == 1) {
+            return list;
+        }
+        ArrayList<E> filteredList = new ArrayList<>();
+        for (int i = 0; i < list.size(); i++) {
+            if (!filteredList.contains(list.get(i))) {
+                filteredList.add(list.get(i));
+            }
+        }
+        return filteredList;
+    }
+}

ch_19/Exercise19_04.java

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+package ch_19;
+
+import java.util.Arrays;
+
+/**
+ * 19.4 (Generic linear search) Implement the following generic method for linear search.
+ * <p>
+ * {@code public static <E extends Comparable<E>>int linearSearch(E[] list, E key) }
+ */
+public class Exercise19_04 {
+    public static void main(String[] args) {
+        Double searchKey = 100.8;
+        Double[] values = new Double[]{100.1, 100.3, 100.0, 100.8, 100.6};
+        System.out.println("Generic LinearSearch returned index: " + linearSearch(values,
+                searchKey) + ". When search key is " + searchKey + " and an Array of Double values is: \n" + Arrays.toString(values));
+    }
+
+
+    public static <E extends Comparable<E>> int linearSearch(E[] list, E key) {
+        for (int i = 0; i < list.length; i++) {
+            if (list[i].compareTo(key) == 0) {
+                return i;
+            }
+
+        }
+        return -1;
+
+    }
+}

ch_19/Exercise19_05.java

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+package ch_19;
+
+import java.util.Arrays;
+
+/**
+ * 19.5 (Maximum element in an array) Implement the following method that returns the
+ * maximum element in an array.
+ * <p>
+ * {@code public static <E extends Comparable<E>> E max(E[] list) }
+ */
+public class Exercise19_05 {
+    public static void main(String[] args) {
+        //Test the method
+        Double[] values = new Double[]{4400.1, 1203.3, 3100.0, 18700.8, 4100.6};
+        System.out.println("Generic Max method returned: " + max(values) + ". When passed this Array of values: " +
+                " \n" + Arrays.toString(values));
+    }
+
+    public static <E extends Comparable<E>> E max(E[] list) {
+        E maxValue = list[0];
+        for (int i = 1; i < list.length; i++) {
+            if (list[i].compareTo(maxValue) > 0) {
+                maxValue = list[i];
+            }
+        }
+        return maxValue;
+    }
+
+}