///
/// conditional expressions
///
main(List<String> args) {
  // if-else
  var marks = 70;
  if (marks >= 90 && marks < 100) {
    print("A+ grade");
  } else if (marks >= 80 && marks < 90) {
    print("A grade");
  } else if (marks >= 70 && marks < 80) {
    print("B grade");
  } else if (marks >= 60 && marks < 70) {
    print("C grade");
  } else if (marks > 30 && marks < 60) {
    print("D grade");
  } else if (marks >= 0 && marks < 30) {
    print("You have failed");
  } else {
    print("Invalid Marks. Please try again !");
  }

  // condition ? exp1 : exp2
  int a = 2;
  int b = 3;
  int smallNumber = a < b ? a : b;
  print("$smallNumber is smaller");

  // exp1 ?? exp2
  String name;
  print(name ?? "Guest User");

  // Switch Case Statements: Applicable for only 'int' and 'String'
  String grade = 'A';
  switch (grade) {
    case 'A':
      print("Excellent grade of A");
      break;
    case 'B':
      print("Very Good !");
      break;
    case 'C':
      print("Good enough. But work hard");
      break;
    case 'F':
      print("You have failed");
      break;
    default:
      print("Invalid Grade");
  }

}