public static void Main()
Console.WriteLine("Hello Diego");
Console.WriteLine("Input class grade: ");
grade = Convert.ToInt32(Console.ReadLine());
classification = "grade-schooler";
classification = "Middle-schooler";
classification = "freshman";
classification = "sophomore";
classification = "junior";
classification = "senior";
classification = "undefined";
if(classification == "undefined")
Console.WriteLine("...invalid grade...");
Console.WriteLine("Student is a {0}.", classification);