Exception Handling (try-catch)

🎯 Mục tiêu: Xử lý errors với try-catch.

---

💡 Cú pháp

try {
  var result = riskyOperation();
} on FormatException catch (e) {
  print("Format error: $e");
} on Exception catch (e) {
  print("Exception: $e");
} catch (e, stackTrace) {
  print("Error: $e");
  print("Stack: $stackTrace");
} finally {
  print("Cleanup");
}

---

📝 Throw

void validateAge(int age) {
  if (age < 0) {
    throw ArgumentError("Age cannot be negative");
  }
  if (age > 150) {
    throw RangeError("Age out of range");
  }
}

---

🔧 Custom Exception

class ValidationException implements Exception {
  final String message;
  ValidationException(this.message);

  @override
  String toString() => "ValidationException: $message";
}

throw ValidationException("Invalid email");

---

✅ Checklist

• try-catch-finally
• on Type catch cho specific errors
• Custom exceptions với implements Exception

---