complete Main file

.idea/misc.xml

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="ProjectRootManager" version="2" project-jdk-name="25" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_21" project-jdk-name="21" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/out" />
   </component>
 </project>

src/CourseRegistrationStarter/Main.java

@@ -4,11 +4,26 @@ public class Main {
     public static void main(String[] args) {
         // TODO:
         // 1. Create at least 3 courses
+        Course AdvancedProgramming = new Course("Advanced Programming","123",2);
+        Course DataStructures = new Course("Data Structures","456",3);
+        Course DatabaseSystems = new Course("Database Systems","789",2);
         // 2. Create 1 student
+        Student Hadi = new Student("Hadi","40033037");
         // 3. Create a registration system
+        RegistrationSystem CS = new RegistrationSystem();
         // 4. Add courses to the system
+        CS.addCourseToSystem(AdvancedProgramming);
+        CS.addCourseToSystem(DataStructures);
+        CS.addCourseToSystem(DatabaseSystems);
         // 5. Register the student in some courses
+        Hadi.addCourse(DataStructures);
+        Hadi.addCourse(DatabaseSystems);
+        Hadi.addCourse(AdvancedProgramming);
         // 6. Drop one course
+        Hadi.dropCourse(DataStructures);
         // 7. Print the final registered course list
+        Hadi.showRegisteredCourses();
+        CS.showAllCourses();
+
     }
 }

src/CourseRegistrationStarter/RegistrationSystem.java

@@ -9,16 +9,34 @@ public class RegistrationSystem {
     }
 
     public void addCourseToSystem(Course c) {
-        // TODO: Add the course to the system
+        if (courses.contains(c)) {
+            return;
+        }
+        else {
+            courses.add(c);
+        }
     }
 
     public Course findCourseByCode(String code) {
-        // TODO: Search for a course by course code
+        for (Course c : courses) {
-        // Return the matching course if found, otherwise return null
+            if (c.getCourseCode().equals(code)) {
+                return c;
+            }
+        }
         return null;
     }
 
     public void showAllCourses() {
-        // TODO: Print all courses in the system
+        for (Course c : courses) {
+            System.out.println(c.getCourseName()+" "+c.getCourseCode()+" "+c.getCapacity());
+        }
+    }
+    public Course findCourseByName(String name) {
+        for (Course c : courses) {
+            if (c.getCourseName().equals(name)) {
+                return c;
+            }
+        }
+        return null;
     }
 }

src/CourseRegistrationStarter/Student.java

@@ -21,19 +21,28 @@ public class Student {
     }
 
     public boolean addCourse(Course c) {
-        // TODO: Register the student in the course if capacity allows
+        if (registeredCourses.size() <= 3) {
-        // Return true if registration was successful, otherwise false
+            if (c.getCapacity() > 0) {
+                registeredCourses.add(c);
+                c.reduceCapacity();
+                return true;
+            }
+        }
         return false;
     }
 
     public boolean dropCourse(Course c) {
-        // TODO: Remove the course from the student's list
+        if (registeredCourses.contains(c)) {
-        // Restore the course capacity if removal was successful
+            registeredCourses.remove(c);
-        // Return true if the course was dropped, otherwise false
+            c.increaseCapacity();
+            return true;
+        }
         return false;
     }
 
     public void showRegisteredCourses() {
-        // TODO: Print all registered courses
+        for (Course c : registeredCourses) {
+            System.out.println(c.getCourseName()+" "+c.getCourseCode());
+        }
     }
 }