What is the difference between concepts R and exceptions?

In programming, including Flutter, R usually denotes the return value of a function, which indicates the result of execution, such as an error code or successful completion. This is a common way to convey status information without interrupting the flow of execution.

Exceptions are error handling mechanisms where, upon encountering an error, the program execution is interrupted and control is transferred to an exception handling block (try-catch). Exceptions allow separating main code from error handling code and reacting conveniently to unexpected situations.

Main differences:

• Return value (R) requires the calling code to check the result and decide what to do in case of an error.
• Exceptions automatically interrupt the normal flow and transfer control to a handler, simplifying error handling but potentially complicating flow understanding.

Example in Dart (Flutter):

int divide(int a, int b) {
  if (b == 0) return -1; // R - error code
  return a ~/ b;
}

int divideWithException(int a, int b) {
  if (b == 0) throw ArgumentError('Division by zero');
  return a ~/ b;
}

void main() {
  var result = divide(10, 0);
  if (result == -1) {
    print('Error: division by zero');
  }

  try {
    var res = divideWithException(10, 0);
  } catch (e) {
    print('Caught exception: $e');
  }
}