Complete all classes .

src/CourseRegistrationStarter/Main.java

@@ -4,11 +4,36 @@ public class Main {
     public static void main(String[] args) {
         // TODO:
         // 1. Create at least 3 courses
+
+        Course course1 = new Course("Advanced Programming" , "AP1404", 2) ;
+        Course course2 = new Course("Data Structures", "DS2201", 1) ;
+        Course course3 = new Course("Database Systems", "DB3301", 3) ;
+        
         // 2. Create 1 student
+        
+        Student student1 = new Student ("Ali", "402222001") ;
+        
         // 3. Create a registration system
+
+        RegistrationSystem registrationSystem = new RegistrationSystem() ;
+
         // 4. Add courses to the system
+
+        registrationSystem.addCourseToSystem(course1) ;
+        registrationSystem.addCourseToSystem(course2) ;
+        registrationSystem.addCourseToSystem(course3) ;
+        
         // 5. Register the student in some courses
+
+        student1.addCourse(course1) ;
+        student1.addCourse(course2) ;
+        student1.addCourse(course3) ;
         // 6. Drop one course
+
+        student1.dropCourse(course2) ;
         // 7. Print the final registered course list
+
+        student1.showRegisteredCourses() ;
+        registrationSystem.showAllCourses();
     }
 }