myconstructors.dart

main.dart

class PointA {
  double x = 1.0;
  double y = 2.0;

  // The implicit default constructor sets these variables to (1.0,2.0)
  // PointA();
  
  //
  PointA(String s) : x = double.parse(s), y = double.parse(s);

  @override
  String toString() {
    return 'PointA($x, $y)';
  }
}

void main() {
  PointA point = PointA("1.5");
  print(point);
}
// https://gist.github.com/rena2019/05ec3bede00f5ec8aca55f772e9d9098