private void AddStudent() { StudentNameToAdd.Trim(); if (StudentNameToAdd == "") { throw new ArgumentException("Please type in a name for the student."); } if (StudentNameToAdd.Length < 10) { throw new ArgumentException("We only take students whose name is longer than 10 characters."); } if ((StudentScoreToAdd < 60) || (StudentScoreToAdd > 100)) { throw new ArgumentException("We only take students whose score is between 60 and 100. please give a valid score"); } DateTime Now = DateTime.Now; StringBuilder SB = new StringBuilder(); SB.Append("Student "); SB.Append(StudentNameToAdd); SB.Append(" is added @ "); SB.Append(Now.ToString()); Students.AddAStudent(StudentNameToAdd, StudentScoreToAdd, Now, SB.ToString()); }