Finished Derusting

src/ArrayPractice.java

@@ -1,17 +1,32 @@
+
+
 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] = "Apple";
+    array[1] = "Kiwi";
+    array[2] = "Plum";
+    array[3] = "Coconut";
 
     // Get the value of the array at index 2
+    System.out.println(array[2]);
 
     // Get the length of the array
+    System.out.println(array.length);
 
     // Iterate over the array using a traditional for loop and print out each item
+    for (int i = 0; i < array.length; i++) {
+      System.out.println(array[i]);
+    }
 
     // Iterate over the array using a for-each loop and print out each item
+    for (String element : array) {
+      System.out.println(element);
+    }
 
     /*
      * Reminder!

src/ListPractice.java

@@ -1,27 +1,47 @@
+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> list = new ArrayList<>();
 
     // Add 3 elements to the list (OK to do one-by-one)
+    list.add("BMW");
+    list.add("Porsche");
+    list.add("Mercedes");
 
     // Print the element at index 1
+    System.out.println(list.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)
+    list.set(1, "AUDI");
 
     // Insert a new element at index 0 (the length of the list will change)
+    list.add(0, "VW");
 
     // Check whether the list contains a certain string
+    System.out.println(list.contains("BMW"));
 
     // 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(); i++) {
+      System.out.println("Index: " + i + " Value: " + list.get(i));
+    }
 
     // Sort the list using the Collections library
+    Collections.sort(list);
+    System.out.println(list);
 
     // Iterate over the list using a for-each loop
     // Print each value on a second line
+    for (String value : list) {
+      System.out.println(value);
+    }
 
     /*
      * Usage tip!

src/MapPractice.java

@@ -1,28 +1,48 @@
-
+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("Salmon", 43);
+    map.put("Trout", 175);
+    map.put("Bass", 85);
 
     // Get the value associated with a given key in the Map
+    System.out.println(map.get("Trout"));
 
     // Find the size (number of key/value pairs) of the Map
+    System.out.println(map.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)
+    map.replace("Salmon", 53);
+    System.out.println(map);
 
     // Check whether the Map contains a given key
+    System.out.println(map.containsKey("Bass"));
 
     // Check whether the Map contains a given value
+    System.out.println(map.containsValue(175));
 
     // 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("Key: " + entry.getKey() + ", Value: " + entry.getValue());
+    }
 
     /*
      * 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 negative = -10.93843123f;
+      System.out.println(negative);
 
     // Create an int with a positive value and assign it to a variable
+      int positive = 312;
+      System.out.println(positive);
 
     // Use the modulo % operator to find the remainder when the int is divided by 3
+      int remainder = positive % 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 (positive % 2 == 0) {
+        System.out.println("Even");
+      } else {
+        System.out.println("Odd");
+      }
 
     // Divide the number by another number using integer division
+      int result = positive / 12;
+      System.out.println(result);
 
     /*
      * 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 + " Age: " + age;
+  }
 
   // Implement the below public instance method "birthYear"
   // There should NOT be any print statement in this method.
@@ -28,25 +35,35 @@ public class Person {
    * @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 person = new Person("Bob Smith", 47);
 
     // Create another instance of Person with a different name and age and
     // assign it to a different variable
+    Person person2 = new Person("Joe Smoe", 34);
 
     // Print the first person
+    System.out.println(person);
 
     // Print the second person
+    System.out.println(person2);
 
     // Get the name of the first person and store it in a local variable
+    String name1 = person.name;
+    System.out.println(name1);
 
     // 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 = person.birthYear(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> set = new HashSet<>();
 
     // Add 3 elements to the set
     // (It's OK to do it one-by-one)
+    set.add("Blue");
+    set.add("Green");
+    set.add("Red");
 
     // Check whether the Set contains a given String
+    System.out.println(set.contains("Red"));
 
     // Remove an element from the Set
+    System.out.println(set.remove("Green"));
 
     // Get the size of the Set
+    System.out.println(set.size());
 
     // Iterate over the elements of the Set, printing each one on a separate line
+    for (String element : set) {
+      System.out.println(element);
+    }
 
     /*
      * Warning!

src/StringPractice.java

@@ -1,25 +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 fish = "Salmon";
 
     // Find the length of the string
+    System.out.println(fish.length());
 
     // Concatenate (add) two strings together and reassign the result
-
+    String species = "Chinook";
+    fish = species + " " + fish; 
+    System.out.println(fish);
     // Find the value of the character at index 3
+    System.out.println(fish.charAt(3));
 
     // Check whether the string contains a given substring (i.e. does the string have "abc" in it?)
+    System.out.println(fish.contains("abc"));
 
     // Iterate over the characters of the string, printing each one on a separate line
+    for (int i = 0; i < fish.length(); i++) {
+      System.out.println(fish.charAt(i));
+    }
 
     // Create an ArrayList of Strings and assign it to a variable
+    List<String> list = new ArrayList<>();
 
     // Add multiple strings to the List (OK to do one-by-one)
+    list.add("Chinook");
+    list.add("Coho");
+    list.add("Chum");
+    list.add("Pink");
+    list.add("Sockeye");
 
     // 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 types = String.join(", ", list);
+    System.out.println(types);
 
     // Check whether two strings are equal
+    String a = "Apple";
+    String b = "Pear";
+
+    System.out.println(a.equals(b));
 
     /*
      * Reminder!

toRefresh.md

@@ -2,4 +2,6 @@
 
 As you work through this exercise, write down anything that you needed to look up or struggled to remember here. It can be just a word or two (e.g. "joining strings"). You can use this as a guide of what to make extra sure you're refreshed on before exams and interviews.
 
-- 
+- Floats
+- String Concatenation
+- Iterating Over EntrySet in Maps