Complete code

src/main/java/Main.java

@@ -71,9 +71,10 @@ public class Main {
         switch (choice) {
             case 1:
                 success = school.registerStudent(username, password);
-                if (success) {
+                if(success){
                     System.out.println(" Student registered successfully!");
-                } else {
+                }
+                else{
                     System.out.println(" Username already exists!");
                 }
                 break;
@@ -109,9 +110,10 @@ public class Main {
         switch (choice) {
             case 1:
                 Student student = school.loginStudent(username, password);
-                if (student != null) {
+                if(student != null){
                     studentMenu(student);
-                } else {
+                }
+                else{
                     System.out.println(" Invalid username or password!");
                 }
                 break;
@@ -151,7 +153,7 @@ public class Main {
                     enrollInCourse(student);
                     break;
                 case 3:
-                    System.out.print(student.getMyCoursesDisplay());
+                    //System.out.print(student.getMyCoursesDisplay());
                     break;
                 case 4:
                     System.out.println(" Goodbye, " + student.getUsername() + "!");
@@ -163,21 +165,12 @@ public class Main {
     }
 
     private static void enrollInCourse(Student student) {
-        System.out.print(school.getAllCoursesDisplay());
-        System.out.print("\nEnter Course ID to enroll: ");
-        int courseId = getIntInput();
-
-        Course course = school.findCourseById(courseId);
-        if (course == null) {
-            System.out.println(" Course not found! Please enter a valid ID.");
-            return;
-        }
-
-        if (student.enrollInCourse(course)) {
-            System.out.println(" Successfully enrolled in " + course.getName());
-        } else {
-            System.out.println(" You are already enrolled in this course!");
-        }
+        System.out.println("\n Select a course:\n");
+        school.getAllCoursesDisplay();
+        System.out.println();
+        String courseName = scanner.toString();
+        Course course = school.findCourseByName(courseName);
+        student.enrollInCourse(course);
     }
 
     // ==================== TEACHER MENU ====================

src/main/java/models/Student.java

@@ -11,8 +11,12 @@ public class Student extends User {
         this.enrolledCourses = new ArrayList<>();
     }
 
-    public boolean enrollInCourse(Course course) {
-        if (enrolledCourses.contains(course)) {
+    public List<Course> getEnrolledCourses() {
+        return enrolledCourses;
+    }
+
+    public boolean enrollInCourse(Course course){
+        if(enrolledCourses.contains(course)){
             return false;
         }
         enrolledCourses.add(course);
@@ -20,19 +24,17 @@ public class Student extends User {
         return true;
     }
 
-    public List<Course> getEnrolledCourses() {
-        return enrolledCourses;
-    }
-
-    public String getMyCoursesDisplay() {
-        if (enrolledCourses.isEmpty()) {
-            return " You are not enrolled in any course yet.";
-        } else {
+    public String getMyCoursesDisplay(){
+        if(enrolledCourses.isEmpty()){
+            return "You are not enrolled in any course yet.";
+        }
+        else{
             StringBuilder sb = new StringBuilder("\n My Courses:\n");
-            for (int i = 0; i < enrolledCourses.size(); i++) {
-                sb.append("  ").append(i+1).append(". ").append(enrolledCourses.get(i)).append("\n");
+            for(int i = 0; i < enrolledCourses.size(); i++){
+                sb.append("   ").append(i + 1).append(enrolledCourses.get(i)).append("\n");
             }
             return sb.toString();
         }
     }
+
 }

src/main/java/services/SchoolSystem.java

@@ -16,25 +16,27 @@ public class SchoolSystem {
     }
 
     // ========== Student Management ==========
-    public boolean registerStudent(String username, String password) {
-        if (findStudent(username) != null) {
+    public boolean registerStudent(String username, String password){
+        if(findStudent(username) != null){
             return false;
         }
         students.add(new Student(username, password));
         return true;
     }
 
-    public Student loginStudent(String username, String password) {
+    public Student loginStudent(String username, String password){
         Student student = findStudent(username);
-        if (student != null && student.checkPassword(password)) {
+        if(student != null && student.checkPassword(password)){
             return student;
         }
         return null;
     }
 
-    private Student findStudent(String username) {
-        for (Student s : students) {
-            if (s.getUsername().equals(username)) return s;
+    public Student findStudent(String username){
+        for(Student s : students){
+            if(s.getUsername().equals(username)){
+                return s;
+            }
         }
         return null;
     }
@@ -65,8 +67,8 @@ public class SchoolSystem {
 
     // ========== Course Management ==========
     public boolean addCourseToSystem(String courseName) {
-        for (Course c : allCourses) {
-            if (c.getName().equals(courseName)) {
+        for(Course c : allCourses){
+            if(c.getName().equals(courseName)){
                 return false;
             }
         }
@@ -75,9 +77,11 @@ public class SchoolSystem {
     }
 
     public Course findCourseById(int id) {
-        for (Course c : allCourses) {
-            if (c.getId() == id) return c;
-        }
+       for(Course c : allCourses){
+           if(c.getId() == id){
+               return c;
+           }
+       }
         return null;
     }