Completed Java Derusting

src/ArrayPractice.java

@@ -2,17 +2,36 @@ public class ArrayPractice {
   public static void main(String[] args) {
     // Create an array of Strings of size 4
 
+    String[] array = 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
+    array[0] = "Danny";
+    array[1] = "Programming";
+    array[2] = "Green River College";
+    array[3] = "Auburn Center";
 
     // Get the value of the array at index 2
 
+    String index2 = array[2];
+
+    System.out.println("Index 2 value is " + index2);
+
     // Get the length of the array
 
+    int arrayLength = array.length;
+
     // Iterate over the array using a traditional for loop and print out each item
+    for(int i = 0; i <= arrayLength - 1; i++){
+      System.out.println(array[i]);;
+    }
 
     // Iterate over the array using a for-each loop and print out each item
 
+    for(String string : array){
+      System.out.println(string);
+    }
+
     /*
      * Reminder!
      * 

src/ListPractice.java

@@ -1,27 +1,52 @@
+import java.util.ArrayList;
+import java.util.Collection;
+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> list = new ArrayList<>();
+
     // Add 3 elements to the list (OK to do one-by-one)
+    list.add("One");
+    list.add("two");
+    list.add("three");
 
     // Print the element at index 1
+    System.out.println(list.get(0));
 
     // Replace the element at index 1 with a new value
     // (Do not insert a new value. The length of the list should not change)
+    list.set(0, "four");
+
 
     // Insert a new element at index 0 (the length of the list will change)
+    list.add(0, "five");
 
     // Check whether the list contains a certain string
 
+    list.contains("five");
+
     // Iterate over the list using a traditional for-loop.
     // Print each index and value on a separate line
 
+    for(int i = 0; i <= list.size() - 1; i++){
+      System.out.println(i + " : " + list.get(i));
+    }
+
     // Sort the list using the Collections library
 
+    Collections.sort(list);
+
     // Iterate over the list using a for-each loop
     // Print each value on a second line
+    for(String num : list){
+      System.out.println(num);
+    }
 
     /*
      * Usage tip!

src/MapPractice.java

@@ -1,29 +1,61 @@
 
+import java.util.HashMap;
+import java.util.Map;
+
+
 
 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("Seattle", 1);
+    map.put("California", 2);
+    map.put("Auburn",  3);
+
     // Get the value associated with a given key in the Map
 
+    map.get("Seattle");
+
+
     // Find the size (number of key/value pairs) of the Map
 
+    map.size();
+
     // Replace the value associated with a given key (the size of the Map shoukld not change)
 
+    map.replace("Seattle", 10);
+
     // Check whether the Map contains a given key
 
+    map.containsKey("Seattle");
+
     // Check whether the Map contains a given value
+    map.containsValue(10);
 
     // 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 (int value : map.values()){
+      System.out.println(value);
+    }
+
     // Iterate over the entries in the map, printing each key and value
 
+    for(Map.Entry<String, Integer> entry : map.entrySet()){
+      System.out.println(entry);
+    }
+
     /*
      * Usage tip!
      * 

src/NumberPractice.java

@@ -2,16 +2,26 @@ public class NumberPractice {
   public static void main(String args[]) {
     // Create a float with a negative value and assign it to a variable
 
+    float negativeFloat = -.05f;
     // Create an int with a positive value and assign it to a variable
 
+    int num = 6;
     // Use the modulo % operator to find the remainder when the int is divided by 3
 
+    int remainder = num % 3;
     // 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(num % 2 == 0){
+      System.out.println("Even");
+    } else{
+      System.out.println("Odd");
+    }
+
     // Divide the number by another number using integer division
+    int divValue = num / 3 ;
 
     /*
      * Reminder!

src/Person.java

@@ -4,63 +4,83 @@
  */
 
 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
+    // Declare a public String instance variable for the name of the person
 
+    public String name;
 
-  // Create a constructor that takes the name and age of the person
-  // and assigns it to the instance variables
+    // Declare a private int instance variable for the age of the person
+    private int age;
 
+    // Create a constructor that takes the name and age of the person
+    // and assigns it to the instance variables
+    public Person(String name, int age) {
+        this.name = name;
+        this.age = age;
+    }
 
-  // Create a toString method that gives the name and age of the person
-
-
-  // Implement the below public instance method "birthYear"
-  // There should NOT be any print statement in this method.
-  /**
-   * birthYear returns the year the person was born.
-   * 
-   * The birth year is calculated by subtracting the person's age from currentYear
-   * that's passed in as an int. It assumes that the person's birthday has already
-   * passed this year.
-   * 
-   * @param currentYear an int for the current year
-   * @return The year the person was born
-   */
-  // (create the instance method here)
-
-
-  public static void main(String[] args) {
-    // Create an instance of Person
-
-    // Create another instance of Person with a different name and age and
-    // assign it to a different variable
-
-    // Print the first person
-
-    // Print the second person
-
-    // Get the name of the first person and store it in a local variable
-
-    // 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.
-
-    // In a separate statement, print the local variable holding the birth year.
+    // Create a toString method that gives the name and age of the person
+    @Override
+    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.
     /**
-     * Terminology!
-     * 
-     * A class is the overall definition, like a blueprint.
-     * An instance is a specific object made according to that definition.
-     * We use "instance" and "object" to mean the same thing.
-     * 
-     * For example, if there is a Person class, we can make an instance of a specific person: Auberon.
-     * 
-     * There can be many instances for the same class. For example: Auberon, Xinting, Baya are all
-     * different instances of the Person class.
-     * 
-     * Each instance has its own instance variables: Auberon's age can be different from Baya's age.
+     * birthYear returns the year the person was born.
+     *
+     * The birth year is calculated by subtracting the person's age from
+     * currentYear that's passed in as an int. It assumes that the person's
+     * birthday has already passed this year.
+     *
+     * @param currentYear an int for the current year
+     * @return The year the person was born
      */
-  }
+    // (create the instance method here)
+    public int birthYear(int currentYear) {
+        return currentYear - age;
+    }
+
+    public static void main(String[] args) {
+        // Create an instance of Person
+
+        Person person1 = new Person("Danny", 21);
+        // Create another instance of Person with a different name and age and
+        // assign it to a different variable
+
+        Person person2 = new Person("Jordan", 22);
+
+        // Print the first person
+        System.out.println(person1);
+
+        // Print the second person
+        System.out.println(person2);
+
+        // Get the name of the first person and store it in a local variable
+        String personOneName = person1.name;
+
+        // 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 birthYear = person1.birthYear(2025);
+
+        // In a separate statement, print the local variable holding the birth year.
+        System.out.println("Birth Year: " + birthYear);
+        /**
+         * Terminology!
+         *
+         * A class is the overall definition, like a blueprint. An instance is a
+         * specific object made according to that definition. We use "instance"
+         * and "object" to mean the same thing.
+         *
+         * For example, if there is a Person class, we can make an instance of a
+         * specific person: Auberon.
+         *
+         * There can be many instances for the same class. For example: Auberon,
+         * Xinting, Baya are all different instances of the Person class.
+         *
+         * Each instance has its own instance variables: Auberon's age can be
+         * different from Baya's age.
+         */
+    }
 }

src/SetPractice.java

@@ -1,18 +1,37 @@
+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> set = new HashSet<>();
+
     // Add 3 elements to the set
     // (It's OK to do it one-by-one)
 
+    set.add("String 1");
+    set.add("String 2");
+    set.add("String 3");
+
     // Check whether the Set contains a given String
 
+    set.contains("String 1");
+
     // Remove an element from the Set
 
+    set.remove("String 1");
+
     // Get the size of the Set
 
+    set.size();
+
     // Iterate over the elements of the Set, printing each one on a separate line
 
+    for(String string : set){
+      System.out.println(string);
+    }
+
     /*
      * Warning!
      *