static void Main(string[] args)
{
StudentSystem studentSystem = new StudentSystem();
string input;
while ((input = Console.ReadLine()) != "Exit")
{
var tokents = input.Split()
.ToArray();
string command = tokents[0];
string name = tokents[1];
if (command == "Create")
{
int age = int.Parse(tokents[2]);
double grade = double.Parse(tokents[3]);
string comment = GetComment(grade);
studentSystem.AddStudent(name, age, grade, comment);
}
else if (command == "Show")
{
studentSystem.ShowStudent(name);
}
}
}