98% done

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[] firstArray = 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
 
+    firstArray[0] = "one";
+    firstArray[1] = "two";
+    firstArray[2] = "three";
+    firstArray[3] = "four";
+
     // Get the value of the array at index 2
 
+    System.out.println(firstArray[2]);
+
     // Get the length of the array
+
+    System.out.println(firstArray.length);
 
     // Iterate over the array using a traditional for loop and print out each item
 
+    for(int i = 0; i < firstArray.length; i++){
+      System.out.println(firstArray[i]);
+    }
+
     // Iterate over the array using a for-each loop and print out each item
 
+    for(String fString: firstArray){
+      System.out.println("value:" +fString);
+    }
+
     /*
      * Reminder!
      * 

src/ListPractice.java

@@ -1,28 +1,55 @@
+import java.util.ArrayList;
+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
 
+    ArrayList<String> firstList = new ArrayList<>();
+
     // Add 3 elements to the list (OK to do one-by-one)
 
+    firstList.add("first");
+    firstList.add("second");
+    firstList.add("third");
+
     // Print the element at index 1
 
+    System.out.println(firstList.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)
 
+    firstList.set(1,"four");
+
     // Insert a new element at index 0 (the length of the list will change)
 
+    firstList.add(0, "five");
+
     // Check whether the list contains a certain string
 
+    firstList.contains("first");
+
     // Iterate over the list using a traditional for-loop.
     // Print each index and value on a separate line
 
+    for(int i = 0; i < firstList.size()-1; i++){
+      System.out.println(firstList.get(i));
+    }
+
     // Sort the list using the Collections library
 
+    Collections.sort(firstList);
+
     // Iterate over the list using a for-each loop
     // Print each value on a second line
 
+    for(String values: firstList){
+      System.out.println(values);
+    }
+
     /*
      * Usage tip!
      * 

src/MapPractice.java

@@ -1,29 +1,52 @@
-
+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> firstHashMap = new HashMap<String, Integer>();
+
     // Put 3 different key/value pairs in the Map
     // (it's OK to do this one-by-one)
 
+    firstHashMap.put("first", 1);
+    firstHashMap.put("second", 2);
+    firstHashMap.put("third", 3);
+
     // Get the value associated with a given key in the Map
 
+    firstHashMap.get("first");
+
     // Find the size (number of key/value pairs) of the Map
 
+    firstHashMap.size();
+
     // Replace the value associated with a given key (the size of the Map shoukld not change)
 
+    firstHashMap.put("first", 4);
+
     // Check whether the Map contains a given key
 
+    firstHashMap.containsKey("first");
+
     // Check whether the Map contains a given value
 
+    firstHashMap.containsValue(4);
+
     // Iterate over the keys of the Map, printing each key
 
+    System.out.println(firstHashMap.keySet());
+
     // Iterate over the values of the map, printing each value
 
+    System.out.println(firstHashMap.values());
+
     // Iterate over the entries in the map, printing each key and value
 
+    System.out.println(firstHashMap.entrySet());
+
     /*
      * Usage tip!
      * 

src/NumberPractice.java

@@ -2,17 +2,32 @@ public class NumberPractice {
   public static void main(String args[]) {
     // Create a float with a negative value and assign it to a variable
 
+    float neg = -1;
+
     // Create an int with a positive value and assign it to a variable
 
+    int pos = 1;
+
     // Use the modulo % operator to find the remainder when the int is divided by 3
 
+    int rema = pos%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.
 
+    int userInput = 28;
+    if(0 == userInput%2){
+      System.out.println("Even");
+    }else{
+      System.out.println("Odd");
+    }
+
     // Divide the number by another number using integer division
 
+    int div = rema/pos; 
+
     /*
      * Reminder!
      * 

src/Person.java

@@ -7,13 +7,28 @@ 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;
+  public int age;
 
   // Create a constructor that takes the name and age of the person
   // and assigns it to the instance variables
 
+  Person(){
+    name = "Unknown";
+    age = 0;
+  }
+
+  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 "Person{name= "+ name + " , age=" + age + "}";
+  }
 
   // Implement the below public instance method "birthYear"
   // There should NOT be any print statement in this method.
@@ -33,15 +48,25 @@ public class Person {
   public static void main(String[] args) {
     // Create an instance of Person
 
+    Person unKnown = new Person(null, 0);
+
     // Create another instance of Person with a different name and age and
     // assign it to a different variable
 
+    Person dani = new Person("Daniel", 28);
+
     // Print the first person
 
+    System.out.println(unKnown.toString());
+
     // Print the second person
 
+    System.out.println(dani.toString());
+
     // Get the name of the first person and store it in a local variable
 
+    String idName = dani.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.

src/SetPractice.java

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

src/StringPractice.java

@@ -1,26 +1,54 @@
+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 checkSize = "Danny";
+
     // Find the length of the string
 
+    checkSize.length();
+
     // Concatenate (add) two strings together and reassign the result
 
+    checkSize = "Danny" + " DEV28";
+
     // Find the value of the character at index 3
 
+    String loader = "";
+    char[] refract = checkSize.toCharArray();
+    loader += refract[3];
+
     // Check whether the string contains a given substring (i.e. does the string have "abc" in it?)
 
+    checkSize.contains("Danny");
+
     // Iterate over the characters of the string, printing each one on a separate line
 
+    for(char i : refract){
+      System.out.println(i);
+    }
+
     // Create an ArrayList of Strings and assign it to a variable
 
+    ArrayList<String> strList = new ArrayList<>();
+
     // Add multiple strings to the List (OK to do one-by-one)
 
+    strList.add("Danny");
+    strList.add("DEV28");
+    strList.add("GitHub");
+
     // 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 bindingStr = String.join(" ", strList);
+
     // Check whether two strings are equal
 
+    boolean rEqual = bindingStr.equals(checkSize);
+
     /*
      * Reminder!
      *