implement triangle method

src/CourseRegistrationStarter/Course.java

@@ -5,7 +5,8 @@ public class Course {
     private String courseCode;
     private int capacity;
 
-    public Course(String courseName, String courseCode, int capacity) {
+    public Course(String courseName, String courseCode, int capacity)
+    {
         this.courseName = courseName;
         this.courseCode = courseCode;
         this.capacity = capacity;
@@ -23,7 +24,8 @@ public class Course {
         return capacity;
     }
 
-    public boolean reduceCapacity() {
+    public boolean reduceCapacity()
+    {
         if (capacity > 0) {
             capacity--;
             return true;

src/CourseRegistrationStarter/Main.java

@@ -1,7 +1,8 @@
 package CourseRegistrationStarter;
 
 public class Main {
-    public static void main(String[] args) {
+    public static void main(String[] args)
+    {
         // TODO:
         // 1. Create at least 3 courses
         // 2. Create 1 student

src/CourseRegistrationStarter/RegistrationSystem.java

@@ -1,24 +1,53 @@
 package CourseRegistrationStarter;
 import java.util.ArrayList;
 
-public class RegistrationSystem {
+public class RegistrationSystem
+    {
     private ArrayList<Course> courses;
 
-    public RegistrationSystem() {
+    public RegistrationSystem()
+    {
         courses = new ArrayList<>();
     }
 
-    public void addCourseToSystem(Course c) {
-        // TODO: Add the course to the system
+    public void addCourseToSystem(Course c)
+    {
+        // Add the course to the system
+        courses.add(c);
+        System.out.println("Course " + c.getCourseName() + " added to the system."); // Feedback message
     }
 
-    public Course findCourseByCode(String code) {
-        // TODO: Search for a course by course code
-        // Return the matching course if found, otherwise return null
+    public Course findCourseByCode(String code)
+    {
+        // Search for a course by course code
+        for (Course c : courses)
+        {
+            if (c.getCourseCode().equals(code))
+            {
+                // Return the matching course if found
+                return c;
+            }
+        }
+        // otherwise return null
+        System.out.println("Course with code " + code + " not found."); // Feedback message
         return null;
     }
 
-    public void showAllCourses() {
-        // TODO: Print all courses in the system
+    public void showAllCourses()
+    {
+        // Print all courses in the system
+        System.out.println("\n--- All Courses in the System ---");
+        if (courses.isEmpty())
+        {
+            System.out.println("No courses available in the system.");
+        }
+        else
+        {
+            for (Course c : courses)
+            {
+                System.out.println("Name: " + c.getCourseName() + ", Code: " + c.getCourseCode() + ", Capacity: " + c.getCapacity());
+            }
+        }
+        System.out.println("-------------------------------\n");
     }
 }

src/CourseRegistrationStarter/Student.java

@@ -1,12 +1,14 @@
 package CourseRegistrationStarter;
 import java.util.ArrayList;
 
-public class Student {
+public class Student
+    {
     private String name;
     private String studentId;
     private ArrayList<Course> registeredCourses;
 
-    public Student(String name, String studentId) {
+    public Student(String name, String studentId)
+    {
         this.name = name;
         this.studentId = studentId;
         this.registeredCourses = new ArrayList<>();
@@ -20,20 +22,55 @@ public class Student {
         return studentId;
     }
 
-    public boolean addCourse(Course c) {
-        // TODO: Register the student in the course if capacity allows
-        // Return true if registration was successful, otherwise false
-        return false;
+    public boolean addCourse(Course c)
+    {
+        // Register the student in the course if capacity allows
+        if (c.reduceCapacity())
+        { // Reduce capacity, returns true if successful (capacity > 0)
+            registeredCourses.add(c);
+            System.out.println(name + " successfully registered for course: " + c.getCourseName());
+            return true;
+        }
+        else
+        {
+            System.out.println(name + " could not register for course " + c.getCourseName() + ". Course is full.");
+            return false;
+        }
     }
 
-    public boolean dropCourse(Course c) {
-        // TODO: Remove the course from the student's list
+    public boolean dropCourse(Course c)
+    {
+        // Remove the course from the student's list
         // Restore the course capacity if removal was successful
-        // Return true if the course was dropped, otherwise false
-        return false;
+        if (registeredCourses.contains(c))
+        {
+            registeredCourses.remove(c);
+            c.increaseCapacity(); // Restore capacity
+            System.out.println(name + " successfully dropped course: " + c.getCourseName());
+            return true;
+        }
+        else
+        {
+            System.out.println(name + " is not registered for course: " + c.getCourseName() + ", cannot drop.");
+            return false;
+        }
     }
 
-    public void showRegisteredCourses() {
-        // TODO: Print all registered courses
+    public void showRegisteredCourses()
+    {
+        // Print all registered courses
+        System.out.println("\n--- Courses Registered by " + name + " ---");
+        if (registeredCourses.isEmpty())
+        {
+            System.out.println(name + " is not registered for any courses.");
+        }
+        else
+        {
+            for (Course c : registeredCourses)
+            {
+                System.out.println("Name: " + c.getCourseName() + ", Code: " + c.getCourseCode());
+            }
+        }
+        System.out.println("------------------------------------\n");
     }
 }