Java Derusting Assignment

src/ArrayPractice.java

@@ -1,17 +1,29 @@
 public class ArrayPractice {
   public static void main(String[] args) {
     // Create an array of Strings of size 4
+    String words[] = new String[4];
 
     // Set the value of the array at each index to be a different String
     // It's OK to do this one-by-one
+    words[0] = "Bike";
+    words[1] = "Car";
+    words[2] = "Boat";
+    words[3] = "Motorcycle";
 
     // Get the value of the array at index 2
+    System.out.println(words[1]);
 
     // Get the length of the array
+    System.out.println(words.length);
 
     // Iterate over the array using a traditional for loop and print out each item
-
+    for (int i = 0; i < words.length; i++) {
+      System.out.println(words[i]);
+    }
     // Iterate over the array using a for-each loop and print out each item
+    for (String word : words) {
+      System.out.println(word);
+    }
 
     /*
      * Reminder!

src/ListPractice.java

@@ -1,28 +1,50 @@
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
 public class ListPractice {
 
 
   public static void main(String[] args) {
     // Create an empty ArrayList of Strings and assign it to a variable of type List
+    List<String> words = new ArrayList<>();
+
 
     // Add 3 elements to the list (OK to do one-by-one)
-
+    words.add("Marvel Comics");
+    words.add("Detective Comics");
+    words.add("Image Comics");
     // Print the element at index 1
+    System.out.println(words.get(1));
 
     // Replace the element at index 1 with a new value
     // (Do not insert a new value. The length of the list should not change)
+    words.set(1, "Dark Horse Comics");
+    System.out.println(words.get(1));
 
     // Insert a new element at index 0 (the length of the list will change)
+    words.add(0, "IDW Publishing");
 
     // Check whether the list contains a certain string
+    System.out.println(words.contains("Dark Horse Comics"));
 
     // Iterate over the list using a traditional for-loop.
-    // Print each index and value on a separate line
+    for (int i = 0; i < words.size(); i++) { 
 
+    // Print each index and value on a separate line
+      System.out.println(words.get(i));
+    }
     // Sort the list using the Collections library
+    System.out.println("before sort: " + words);
+    Collections.sort(words);
+    System.out.println("after sort: " + words);
 
     // Iterate over the list using a for-each loop
-    // Print each value on a second line
+    for (String word : words) {
 
+    // Print each value on a second line
+      System.out.println(word);
+    }
     /*
      * Usage tip!
      * 

src/MapPractice.java

@@ -1,28 +1,51 @@
-
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Set;
 
 public class MapPractice {
   public static void main(String[] args) {
     // Create a HashMap with String keys and Integer values and
     // assign it to a variable of type Map
+    Map<String, Integer> map = new HashMap<>();
 
     // Put 3 different key/value pairs in the Map
     // (it's OK to do this one-by-one)
+    map.put("Xavier", 1);
+    map.put("Jhoanna", 2);
+    map.put("Thor", 3);
 
     // Get the value associated with a given key in the Map
+    int value = map.get("Xavier");
+    System.out.println("The value associated with key: 'Xavier' is " + value);
 
     // Find the size (number of key/value pairs) of the Map
+    System.out.println("The size of the map is: " + map.size());
 
     // Replace the value associated with a given key (the size of the Map shoukld not change)
+     map.replace("Thor", 23);
+     System.out.println(map.get("Thor"));
+     System.out.println(map.size());
 
     // Check whether the Map contains a given key
+    System.out.println(map.containsKey("Xavier"));
 
     // Check whether the Map contains a given value
+    System.out.println(map.containsValue(23));
 
     // Iterate over the keys of the Map, printing each key
+    for (String key : map.keySet()) {
+      System.out.println(key);
+    }
 
     // Iterate over the values of the map, printing each value
+    for (Integer val : map.values()) {
+      System.out.println(val);
+    }
 
     // Iterate over the entries in the map, printing each key and value
+    for (Map.Entry<String, Integer> entry : map.entrySet()) {
+      System.out.println(entry.getKey() + " --> " + entry.getValue());
+    }
 
     /*
      * Usage tip!

src/NumberPractice.java

@@ -1,17 +1,29 @@
 public class NumberPractice {
   public static void main(String args[]) {
     // Create a float with a negative value and assign it to a variable
+    float negativeNum = -10.0f;
 
     // Create an int with a positive value and assign it to a variable
+    int positiveNum = 10;
 
     // Use the modulo % operator to find the remainder when the int is divided by 3
+    int remainder = positiveNum % 3;
+    System.out.println(positiveNum + " % 3 = " + remainder);
 
     // Use the modulo % operator to determine whether the number is even
     // (A number is even if it has a remainder of zero when divided by 2)
     // Use an if-else to print "Even" if the number is even and "Odd"
     // if the number is odd.
+    if (negativeNum % 2 == 0) {
+      System.out.println("Even");
+    }
+    else {
+      System.out.println("Odd");
+    }
 
     // Divide the number by another number using integer division
+    int quotient = positiveNum / 5;
+    System.out.println("Answer: " + quotient);
 
     /*
      * Reminder!

src/Person.java

@@ -5,15 +5,22 @@
 
 public class Person {
   // Declare a public String instance variable for the name of the person
-  // Declare a private int instance variable for the age of the person
+  public String name; // instance variable (can be accessed outside class )
 
+  // Declare a private int instance variable for the age of the person
+  private int age;// can only be accessed within the class (private)
 
   // Create a constructor that takes the name and age of the person
+  public Person(String name, int age) {
   // and assigns it to the instance variables
-
-
+    this.name = name;
+    this.age = age;
+  }
+
   // Create a toString method that gives the name and age of the person
-
+  public String toString() {
+    return "name: " + name + " age: " + age; 
+  }
 
   // Implement the below public instance method "birthYear"
   // There should NOT be any print statement in this method.
@@ -28,25 +35,41 @@ public class Person {
    * @return The year the person was born
    */
   // (create the instance method here)
+  public int birthYear(int currentYear) {
+    int yearOfBirth = currentYear - age;
+    return yearOfBirth;
+  }
+
+  // Getter Method
+  public String getName() {
+    return this.name;
+  }
 
 
   public static void main(String[] args) {
     // Create an instance of Person
+    Person p = new Person("Xavier", 35);
 
     // Create another instance of Person with a different name and age and
     // assign it to a different variable
+    Person pTwo = new Person("Jhoanna", 36);
 
     // Print the first person
+    System.out.println(p);
 
     // Print the second person
+    System.out.println(pTwo);
 
     // Get the name of the first person and store it in a local variable
-
+    System.out.println(p.getName());
+
     // Using the birthYear method, get the birth year of the first person
     // and store it in a local variable. Input the actual current year (e.g. 2025)
     // as the argument.
+    int bornYear = p.birthYear(2025); 
 
     // In a separate statement, print the local variable holding the birth year.
+    System.out.println("The year of birth for " + p.getName() + " is: " + bornYear);
 
     /**
      * Terminology!

src/SetPractice.java

@@ -1,17 +1,30 @@
+import java.util.HashSet;
+import java.util.Set;
+
 public class SetPractice {
   public static void main(String[] args) {
     // Create a HashSet of Strings and assign it to a variable of type Set
+    Set<String> words = new HashSet<>();
 
     // Add 3 elements to the set
     // (It's OK to do it one-by-one)
-
+    words.add("The");
+    words.add("Fantastic");
+    words.add("Four");
+
     // Check whether the Set contains a given String
+    System.out.println(words.contains("Fantastic"));
 
     // Remove an element from the Set
+    words.remove("Four");
 
     // Get the size of the Set
+    System.out.println(words.size());
 
     // Iterate over the elements of the Set, printing each one on a separate line
+    for (String word : words) {
+      System.out.println(word);
+    }
 
     /*
      * Warning!

src/StringPractice.java

@@ -1,26 +1,53 @@
+import java.util.ArrayList;
+
 public class StringPractice {
   public static void main(String[] args) {
     // Create a string with at least 5 characters and assign it to a variable
-
+    String firstName = "Xavier";
     // Find the length of the string
+    int nameLength = firstName.length();
+    System.out.println("Length of name: " + nameLength);
 
     // Concatenate (add) two strings together and reassign the result
+    String lastName = "Lewis";
+
+    String fullName = firstName + " " + lastName;
+
+    System.out.println(fullName);
 
     // Find the value of the character at index 3
+    char c = fullName.charAt(3);
+    System.out.println("The value of the character at index 3 is: " + c);
 
     // Check whether the string contains a given substring (i.e. does the string have "abc" in it?)
+    System.out.println(fullName.contains("abc"));
 
     // Iterate over the characters of the string, printing each one on a separate line
+    for (int i = 0; i < lastName.length(); i++) {
+      char w = lastName.charAt(i);
+      System.out.println("Character at index " + i + " is " + w);
+    }
 
     // Create an ArrayList of Strings and assign it to a variable
+    ArrayList<String> words = new ArrayList<>();
 
     // Add multiple strings to the List (OK to do one-by-one)
+    words.add("Apple");
+    words.add("Banana");
+    words.add("Orange");
 
     // Join all of the strings in the list together into a single string separated by commas
     // Use a built-in method to achieve this instead of using a loop
+    String joinedStrings = String.join("," , words);
+    System.out.println(joinedStrings);
 
     // Check whether two strings are equal
-
+    if (firstName.equals(lastName)) {
+      System.out.println("equal");
+    } else {
+      System.out.println("not equal");
+    }
+
     /*
      * Reminder!
      *