How do use a Switch Case Statement in Dart

I am trying to understand how the switch is working in the dart. I have very simple code:

methodname(num radians) {
  switch (radians) {
    case 0:
      // do something
      break;
    case PI:
      // do something else
      break;
  }
}

This unfortunately does not work. If left like this the error is: case expressions must have the same type (I think the type is num, but not the editor). If I change 0 to 0.0 it says: The switch type expression double cannot override == operator - I have no idea what this means!

So what is the way to do this switch case? I can turn it onto if/else probably but I wanted to know how to make the switch work and why is it not working in the first place.

I am running the latest stable version of DartEditor.

The comparsion of double values using '==' is not very reliable and should be avoided (not only in Dart but in most languages).

You could do something like

methodname(num radians) {
  // you can adjust this values according to your accuracy requirements
  const myPI = 3142; 
  int r = (radians * 1000).round();

  switch (r) {
    case 0:
      // do something
      break;
    case myPI: 
      // do something else
      break;
  }
}

This question contains some additional information that might interest you

• https://stackoverflow.com/questions/6837007
• https://stackoverflow.com/questions/4915462

some more information:

• https://www.dartlang.org/docs/spec/latest/dart-language-specification.html#h.50ae78s6gbw2
• http://floating-point-gui.de/errors/comparison/