Evaluate Expressions in Switch Statements

switch (mark)
{
    case int n when n >= 80:
        Console.WriteLine("Grade is A");
        break;
    case int n when n >= 60:
        Console.WriteLine("Grade is B");
        break;
    case int n when n >= 40:
        Console.WriteLine("Grade is C");
        break;
    default:
        Console.WriteLine("Grade is D");
        break;
}