DERUSTING ASSIGNMENT

src/ArrayPractice.java

@@ -1,18 +1,25 @@
-public class ArrayPractice {
+public class ArrayPractice { 
   public static void main(String[] args) {
     // Create an array of Strings of size 4
-
+    String [] wordStrings = 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
-
+    wordStrings[0] = "10";
+    wordStrings[1] = "20";    
+    wordStrings[2] = "30";
+    wordStrings[3] = "40";
     // Get the value of the array at index 2
-
+    System.out.println("The value at index 2 is " + wordStrings[2]);
     // Get the length of the array
-
+    System.out.println("The length of the array is " + wordStrings.length);
     // Iterate over the array using a traditional for loop and print out each item
-
+    for (int i = 0; i < wordStrings.length; i++) {
+      System.out.println("The value at index " + i + " is " + wordStrings[i]);
+    }
     // Iterate over the array using a for-each loop and print out each item
-
+    for (String word : wordStrings) {
+      System.out.println("The value is " + word);
+    }
     /*
      * Reminder!
      * 

src/ListPractice.java

@@ -1,28 +1,40 @@
+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> list = new ArrayList<String>();
 
     // Add 3 elements to the list (OK to do one-by-one)
-
+list.add("Apple");
+list.add("Banana");
+list.add("Cherry");
     // Print the element at index 1
-
-    // Replace the element at index 1 with a new value
+System.out.println(list.get(1));
+    // Replace he 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, "Grapes");
     // Insert a new element at index 0 (the length of the list will change)
-
+list.add(0, "Mango");
     // Check whether the list contains a certain string
-
+list.contains("Pineapple");
     // 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 + ": " + 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 (int i = 0; i < list.size(); i++) {
+      System.out.println(list.get(i));
+    }
 
+    }
     /*
      * Usage tip!
      * 
@@ -33,4 +45,3 @@ public static void main(String[] args) {
      * index values a for-each loop is cleaner.
      */
   }
-}

src/MapPractice.java

@@ -1,29 +1,46 @@
-
+import java.util.HashMap;   
 
 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
-
+      HashMap<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("Apple", 1);
+    map.put("Pineapple", 2);
+    map.put("Pear", 3);
+
     // Get the value associated with a given key in the Map
-
+    System.out.println("The value associated with Apple is " + map.get("Apple"));
     // Find the size (number of key/value pairs) of the Map
-
-    // Replace the value associated with a given key (the size of the Map shoukld not change)
-
+    System.out.println("The size of the map is " + map.size());
+    // Replace the value associated with a given key (the size of the Map should not change)
+    map.put("Apple", 5);
     // Check whether the Map contains a given key
-
+   if (map.containsKey("Apple")) {
+     System.out.println("The map contains Apple");
+   }else{
+    System.out.println("The map does not contain Apple");
+   }
     // Check whether the Map contains a given value
-
+    if (map.containsValue(5)) {
+      System.out.println("The map contains the value of 5")
+    }else{
+      System.out.println("The map does not contain the value of 5");
+    }
     // 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 value : map.values()) {
+      System.out.println(value);
+    }
     // Iterate over the entries in the map, printing each key and value
-
+    for (HashMap.Entry<String, Integer> entry : map.entrySet()) {
+      System.out.println("Key: " + entry.getKey() + ", Value: " + entry.getValue());
+    }
     /*
      * Usage tip!
      * 

src/NumberPractice.java

@@ -1,18 +1,25 @@
-public class NumberPractice {
-  public static void main(String args[]) {
+public class NumberPractice {   
+public static void main(String args[]) {
     // Create a float with a negative value and assign it to a variable
-
+float negative_Float = -20;
     // Create an int with a positive value and assign it to a variable
-
+int positive_Int = 200;
     // Use the modulo % operator to find the remainder when the int is divided by 3
+int remainder = positive_Int % 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 evenCheck = positive_Int % 2;
+if (evenCheck == 0) {
+  System.out.println("Even");
+}else {
+  System.out.println("Odd");
+}
     // Divide the number by another number using integer division
-
+int num_Division = positive_Int / 7;
+System.out.println(num_Division);
     /*
      * Reminder!
      * 

src/Person.java

@@ -6,16 +6,26 @@
 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
-
+public String toString() {
+  return "Name: " + name + ", Age: " + age;
+} 
 
   // Implement the below public instance method "birthYear"
+  public int birthYear(int currentYear) {
+    return currentYear - age;
+  }
   // There should NOT be any print statement in this method.
   /**
    * birthYear returns the year the person was born.
@@ -28,26 +38,29 @@ 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 person1 = new Person("Alice", 30);
 
     // Create another instance of Person with a different name and age and
     // assign it to a different variable
-
+    Person person2 = new Person("Bob", 25);
     // 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 firstPersonName = 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 of " + firstPersonName + " is " + birthYear);  
     /**
      * Terminology!
      * 

src/SetPractice.java

@@ -1,18 +1,33 @@
+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<String>();
     // Add 3 elements to the set
     // (It's OK to do it one-by-one)
 
+    set.add("Apple");
+    set.add("Banana");
+    set.add("Cherry"); 
+
     // Check whether the Set contains a given String
+    if (set.contains("Banana")) {
+      System.out.println("The set contains Banana");
+    } else {
+      System.out.println("The set does not contain Banana");
+    }
 
     // Remove an element from the Set
-
+    set.remove("Apple");
+
     // Get the size of the Set
-
+    System.out.println("The size of the set is " + set.size());
     // Iterate over the elements of the Set, printing each one on a separate line
-
+    for (String item : set) {
+      System.out.println(item);
+    }
     /*
      * Warning!
      * 

src/StringPractice.java

@@ -1,26 +1,52 @@
+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[] fruits = {"Apple", "Mango", "Pineapple", "Kiwi", "Watermelon"};
     // Find the length of the string
-
+    for ( String fruit : fruits) {
+      System.out.println("The length of " + fruit + " is " + fruit.length());
+    }
     // Concatenate (add) two strings together and reassign the result
-
+    String joinString = String.join(", ", fruits);
+    System.out.println(joinString);
     // Find the value of the character at index 3
-
+    String fruit = fruits[0];
+    System.out.println("The character at index 3 of " + fruit + " is " + fruit.charAt(3));
     // Check whether the string contains a given substring (i.e. does the string have "abc" in it?)
-
+    for (String fruit : fruits) {
+      if (fruit.contains("abc")) {
+        System.out.println("The string contains abc");
+      } else {
+        System.out.println("The string does not contain abc");
+      }
+    }
+
     // Iterate over the characters of the string, printing each one on a separate line
-
+    for (String fruit : fruits)  {
+      for (int i = 0; i < fruit.length(); i++) {
+        System.out.println(fruit.charAt(i));
+      }
+}
     // Create an ArrayList of Strings and assign it to a variable
-
+    ArrayList<String> List = new ArrayList<String>();
     // Add multiple strings to the List (OK to do one-by-one)
-
+  List.add("Apple");
+  List.add("Mango");
+  List.add("Banana");
     // 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 joinedString = String.join(", ", List);
+    System.out.println(joinedString);
 
     // Check whether two strings are equal
-
+    if (List.get(0).equals("Apple")) {
+      System.out.println("The first string is Apple");
+    } else {
+      System.out.println("The first string is not Apple");
+    }
+
     /*
      * Reminder!
      *