Finished Java derusting

src/ArrayPractice.java

@@ -1,18 +1,30 @@
 public class ArrayPractice {
   public static void main(String[] args) {
     // Create an array of Strings of size 4
+    String[] arrString = 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
+    arrString[0] = "Java";
+    arrString[1] = "HTML";
+    arrString[2] = "CSS";
+    arrString[3] = "C#";
 
     // Get the value of the array at index 2
+    System.out.println(arrString[2]);
 
     // Get the length of the array
+    System.out.println(arrString.length);
 
     // Iterate over the array using a traditional for loop and print out each item
+    for(int i = 0; i < arrString.length; i++){
+      System.out.println(arrString[i]);
+    }
 
     // Iterate over the array using a for-each loop and print out each item
-
+    for(String str : arrString){
+      System.out.println(str);
+    }
     /*
      * Reminder!
      * 

src/ListPractice.java

@@ -1,27 +1,55 @@
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Collections;
+
 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> stringList = new ArrayList<String>();
 
     // Add 3 elements to the list (OK to do one-by-one)
+    stringList.add("Creed");
+    stringList.add("Michael");
+    stringList.add("Andy");
 
     // Print the element at index 1
+    System.out.println(stringList.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)
+    stringList.set(1, "Jim");
+    System.out.println(stringList.get(1));
 
     // Insert a new element at index 0 (the length of the list will change)
+    stringList.add(0, "Dwight");
+    System.out.println(stringList.get(0));
 
     // Check whether the list contains a certain string
+    if(stringList.contains("Kevin")){
+      System.out.println(true);
+    }else{
+      System.out.println(false);
+    }
 
     // Iterate over the list using a traditional for-loop.
     // Print each index and value on a separate line
+    for(int i = 0; i < stringList.size(); i++){
+      System.out.println(stringList.get(i));
+    }
 
     // Sort the list using the Collections library
+    Collections.sort(stringList);
+
 
     // Iterate over the list using a for-each loop
     // Print each value on a second line
+    for(int i = 0; i < stringList.size(); i++){
+      System.out.println(stringList.get(i));
+      System.out.println();
+
+    }
 
     /*
      * Usage tip!

src/MapPractice.java

@@ -1,28 +1,47 @@
-
+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> stringMap = new HashMap<>();
 
     // Put 3 different key/value pairs in the Map
     // (it's OK to do this one-by-one)
+    stringMap.put("Water", 100);
+    stringMap.put("Coffee", 45);
+    stringMap.put("Soda", 10);
 
     // Get the value associated with a given key in the Map
+    System.out.println(stringMap.get("Soda"));
 
     // Find the size (number of key/value pairs) of the Map
+    System.out.println(stringMap.size());
 
-    // Replace the value associated with a given key (the size of the Map shoukld not change)
+    // Replace the value associated with a given key (the size of the Map should not change)
+    stringMap.replace("Coffee", 30);
 
     // Check whether the Map contains a given key
+    System.out.println(stringMap.containsKey("Water"));
 
     // Check whether the Map contains a given value
+    System.out.println(stringMap.containsValue(10));
 
     // Iterate over the keys of the Map, printing each key
+    for(String key : stringMap.keySet()){
+      System.out.println(key);
+    }
 
     // Iterate over the values of the map, printing each value
+    for(int value : stringMap.values()){
+      System.out.println(value);
+    }
 
     // Iterate over the entries in the map, printing each key and value
+    for(String key : stringMap.keySet()){
+      System.out.println("Key: " + key + " Value: " + stringMap.get(key));
+    }
 
     /*
      * Usage tip!

src/NumberPractice.java

@@ -1,17 +1,30 @@
 public class NumberPractice {
   public static void main(String args[]) {
     // Create a float with a negative value and assign it to a variable
+    float negNum = -12;
+    System.out.println(negNum);
 
     // Create an int with a positive value and assign it to a variable
+    int posNum = 7;
+    System.out.println(posNum);
 
     // Use the modulo % operator to find the remainder when the int is divided by 3
+    int remainder = posNum % 3;
+    System.out.println(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(posNum % 2 == 0){
+      System.out.println("Even");
+    }else{
+      System.out.println("Odd");
+    }
 
     // Divide the number by another number using integer division
+    int intDivision = posNum / 3;
+    System.out.println(intDivision);
 
     /*
      * Reminder!

src/Person.java

@@ -6,14 +6,21 @@
 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;
+  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
-
+  @Override
+  public String toString(){
+    return ("Name: " + name + "\nAge: " + age);
+  }
 
   // Implement the below public instance method "birthYear"
   // There should NOT be any print statement in this method.
@@ -28,25 +35,34 @@ public class Person {
    * @return The year the person was born
    */
   // (create the instance method here)
-
+  public int getBirthYear(int currentYear){
+    return currentYear - age;
+  }
 
   public static void main(String[] args) {
     // Create an instance of Person
-
+    Person personA = new Person("Joe", 25);
     // Create another instance of Person with a different name and age and
     // assign it to a different variable
+    Person personB = new Person("Shmo", 23);
 
     // Print the first person
+    System.out.println(personA.toString());
 
     // Print the second person
+    System.out.println(personB.toString());
 
     // Get the name of the first person and store it in a local variable
+    String nameOfOne = personA.name;
+    System.out.println(nameOfOne);
 
     // 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 = personA.getBirthYear(2025);
 
     // In a separate statement, print the local variable holding the birth year.
+    System.out.println(birthYear);
 
     /**
      * 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> stringSet = new HashSet<>();
 
     // Add 3 elements to the set
     // (It's OK to do it one-by-one)
+    stringSet.add("Coffee");
+    stringSet.add("Water");
+    stringSet.add("Soda");
 
     // Check whether the Set contains a given String
+    System.out.println(stringSet.contains("Coffee"));
 
     // Remove an element from the Set
+    stringSet.remove("Coffee");
 
     // Get the size of the Set
+    System.out.println(stringSet.size());
 
     // Iterate over the elements of the Set, printing each one on a separate line
+    for(String str : stringSet){
+      System.out.println(str);
+    }
 
     /*
      * Warning!

src/StringPractice.java

@@ -1,26 +1,49 @@
+import java.util.ArrayList;
+import java.util.List;
+
 public class StringPractice {
   public static void main(String[] args) {
     // Create a string with at least 5 characters and assign it to a variable
+    String faveChar = "Lines";
 
     // Find the length of the string
+    int stringLength = faveChar.length();
+    System.out.println(stringLength);
 
     // Concatenate (add) two strings together and reassign the result
+    faveChar = faveChar + " Strings";
+    System.out.println(faveChar);
 
     // Find the value of the character at index 3
+    System.out.println(faveChar.charAt(3));
 
     // Check whether the string contains a given substring (i.e. does the string have "abc" in it?)
+    System.out.println(faveChar.contains("abc"));
 
     // Iterate over the characters of the string, printing each one on a separate line
+    for(Character ch : faveChar.toCharArray()){
+      System.out.println(ch);
+    }
 
     // Create an ArrayList of Strings and assign it to a variable
-
+    List<String> stringList = new ArrayList<>();
     // Add multiple strings to the List (OK to do one-by-one)
+    stringList.add("BRUBRUBRU");
+    stringList.add("DUHDUHDUH");
+    stringList.add("BAHBAHBAH");
+    stringList.add("RUHRUHRUH");
 
     // 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 joinString = String.join(", ", stringList);
+    System.out.println(joinString);
 
     // Check whether two strings are equal
-
+    if (faveChar.equals(stringList.get(2))) {
+      System.out.println(true);
+    }else{
+      System.out.println(false);
+    }
     /*
      * Reminder!
      *