src/CourseRegistrationStarter/Main.java

@@ -1,14 +1,75 @@
 package CourseRegistrationStarter;
 
+import java.util.Scanner;
+
 public class Main {
     public static void main(String[] args) {
-        // TODO:
-        // 1. Create at least 3 courses
-        // 2. Create 1 student
-        // 3. Create a registration system
-        // 4. Add courses to the system
-        // 5. Register the student in some courses
-        // 6. Drop one course
-        // 7. Print the final registered course list
+        Course course1 = new Course("َAP", "1414", 2);
+        Course course2 = new Course("DS", "2201", 1);
+        Course course3 = new Course("DB", "3301", 3);
+        Student student1 = new Student("Ali", "402222001");
+        RegistrationSystem registrationSystem = new RegistrationSystem();
+        registrationSystem.addCourseToSystem(course1);
+        registrationSystem.addCourseToSystem(course2);
+        registrationSystem.addCourseToSystem(course3);
+
+        boolean isChosen = false;
+        while (!isChosen)
+        {
+            System.out.println("\n--- Menu ---");
+            System.out.println("1) Add course");
+            System.out.println("2) Drop course");
+            System.out.println("3) Show registered courses");
+            System.out.println("4) Show all courses");
+            System.out.println("5) Exit");
+            System.out.print("Enter your choice: ");
+            Scanner in = new Scanner(System.in);
+            int chosen = in.nextInt();
+            if (chosen == 1)
+            {
+                System.out.print("Enter Course Code to add: ");
+                String codeToAdd = in.next();
+                Course courseToAdd = registrationSystem.findCourseByCode(codeToAdd);
+
+                if (courseToAdd != null)
+                {
+                    student1.addCourse(courseToAdd);
+                }
+                else
+                {
+                    System.out.println("Error: Course not found in system.");
+                }
+            }
+            else if (chosen == 2)
+            {
+                System.out.println("\n--- Drop Course ---");
+                System.out.print("Enter Course Code to drop: ");
+                String codeToDrop = in.next();
+                Course courseToDrop = registrationSystem.findCourseByCode(codeToDrop);
+
+                if (courseToDrop != null)
+                {
+                    student1.dropCourse(courseToDrop);
+                }
+            }
+            else if (chosen == 3)
+            {
+                System.out.println("\n--- Registered Courses ---");
+                student1.showRegisteredCourses();
+            }
+            else if (chosen == 4)
+            {
+                System.out.println("\n--- All Available Courses ---");
+                registrationSystem.showAllCourses();
+            }
+            else if (chosen == 5)
+            {
+                isChosen = true;
+            }
+            else
+            {
+                System.out.println("Invalid! Please enter a number between 1 and 5.");
+            }
+        }
     }
 }

src/CourseRegistrationStarter/RegistrationSystem.java

@@ -9,16 +9,35 @@ public class RegistrationSystem {
     }
 
     public void addCourseToSystem(Course c) {
-        // TODO: Add the course to the system
+        courses.add(c);
     }
 
     public Course findCourseByCode(String code) {
-        // TODO: Search for a course by course code
-        // Return the matching course if found, otherwise return null
+        for (Course a : courses)
+        {
+            if (a.getCourseCode().equals(code))
+            {
+                return a;
+            }
+        }
+        return null;
+    }
+    public Course findCourseByName(String name)
+    {
+        for (Course a : courses)
+        {
+            if (a.getCourseName().equals(name))
+            {
+                return a;
+            }
+        }
         return null;
     }
 
     public void showAllCourses() {
-        // TODO: Print all courses in the system
+        for (Course c : courses)
+        {
+            System.out.println(c.getCourseName() + " - " + c.getCourseCode() + " - capacity: " + c.getCapacity());
+        }
     }
 }

src/CourseRegistrationStarter/Student.java

@@ -21,19 +21,59 @@ public class Student {
     }
 
     public boolean addCourse(Course c) {
-        // TODO: Register the student in the course if capacity allows
-        // Return true if registration was successful, otherwise false
+        if (registeredCourses.size() == 5)
+        {
+            System.out.println("Maximum course limit (5) reached.");
+            return false;
+        }
+        for (Course a : registeredCourses)
+        {
+            if (a.getCourseCode().equals(c.getCourseCode()))
+            {
+                System.out.println("Error: you are already registered for this course!");
+                return false;
+            }
+        }
+        if (c.getCapacity() > 0)
+        {
+            registeredCourses.add(c);
+            c.reduceCapacity();
+            System.out.println("Registration was successful.");
+            return true;
+        }
         return false;
     }
 
     public boolean dropCourse(Course c) {
-        // TODO: 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;
+        Course courseToRempove = null;
+        for (Course a : registeredCourses)
+        {
+            if (a.getCourseCode().equals(c.getCourseCode()))
+            {
+                courseToRempove = a;
+                break;
+            }
+        }
+        if (courseToRempove == null)
+        {
+            System.out.println("Error: you are not registered for this course!");
+            return false;
+        }
+        registeredCourses.remove(courseToRempove);
+        System.out.println("Successfully dropped course.");
+        c.increaseCapacity();
+        return true;
     }
 
     public void showRegisteredCourses() {
-        // TODO: Print all registered courses
+        if (registeredCourses.isEmpty())
+        {
+            System.out.println("No courses registered.");
+            return;
+        }
+        for(Course a : registeredCourses)
+        {
+            System.out.println(a.getCourseName() + " - " + a.getCourseCode());
+        }
     }
 }