public void DisplayMenu()
{
bool ContinueOrExit = true;
do
{
Console.WriteLine("If u want to see the students of the private school write 1 in console");
Console.WriteLine("If u want to see the trainers of the private school write 2 in console");
Console.WriteLine("If u want to see the courses of the private school write 3 in console");
Console.WriteLine("If u want to see the assignments of the private school write 4 in console");
Console.WriteLine("If u want to see the students for each course of the private school write 5 in console");
Console.WriteLine("If u want to see the trainers for each course of the private school write 6 in console");
Console.WriteLine("If u want to see the assignments for each course of the private school write 7 in console");
Console.WriteLine("If u want to see the courses for each student of the private school write 8 in console");
Console.WriteLine("If u want to see the assignments for each course for each student of the private school write 9 in console");
Console.WriteLine("\nIf u want to return to Main Menu write 0 from keyboard\n");
string userInput = Console.ReadLine();
ContinueOrExit = CheckToContinueOrExit(userInput);
switch (userInput)
{
case "1":
Console.Clear();
studentService.Display();
break;
case "2":
Console.Clear();
trainerService.Display();
break;
case "3":
Console.Clear();
courseService.Display();
break;
case "4":
Console.Clear();
assignmentService.Display();
break;
case "5":
Console.Clear();
courseService.DisplayStudentsPerCourse();
break;
case "6":
Console.Clear();
courseService.DisplayTrainersPerCourse();
break;
case "7":
Console.Clear();
courseService.DisplayAssignmentsPerCourse();
break;
case "8":
Console.Clear();
studentService.DisplayMultyCoursesPerStudent();
break;
case "9":
Console.Clear();
studentService.DisplayAssignmentsPerCoursePerStudent();
break;
case "0":
Console.Clear();
break;
default:
Console.Clear();
DisplayMenu();
break;
}
} while (ContinueOrExit);
}