Update src/main/java/models/Teacher.java

src/main/java/models/Teacher.java

@@ -32,22 +32,26 @@ public class Teacher extends User {
         return myCourses;
     }
 
-    public void showMyCourses() {
+    public String getMyCoursesDisplay() {
         if (myCourses.isEmpty()) {
-            System.out.println(" You don't teach any course yet.");
+            return " You don't teach any course yet.";
         } else {
-            System.out.println("\n My Courses:");
+            StringBuilder sb = new StringBuilder("\n My Courses:\n");
             for (int i = 0; i < myCourses.size(); i++) {
-                System.out.println("  " + (i+1) + ". " + myCourses.get(i));
+                sb.append("  ").append(i+1).append(". ").append(myCourses.get(i)).append("\n");
             }
+            return sb.toString();
         }
     }
 
-    public void showStudentsInCourse(Course course) {
+    public boolean checkCourseOwnership(Course course) {
+        return myCourses.contains(course);
+    }
+
+    public String getStudentsDisplayForCourse(Course course) {
         if (!myCourses.contains(course)) {
-            System.out.println(" You don't teach this course!");
-            return;
+            return "You don't teach this course!";
         }
-        course.showStudents();
+        return course.getStudentsDisplay();
     }
 }