// Enroll successfull code here
 public string EnrollCourse(Enroll enrull)
 {
     if (enrollGateway.allreadyEnrolled(enrull))
     {
         int rowAffect = enrollGateway.UpdateEnrolledCourse(enrull);
         if (rowAffect > 0)
         {
             return("Enrolled Course Updated Successful");
         }
         else
         {
             return("Operation Failed");
         }
     }
     else
     {
         int rowAffact = enrollGateway.EnrollCourse(enrull);
         if (rowAffact > 0)
         {
             return("Course Enrolledment Successful");
         }
         else
         {
             return("Operation Failed");
         }
     }
 }