Trying to use switch statement insted of if else to find out which value is bigger or smaller

Question

I am a beginner in learning c# (and any coding language) I am trying to use switch statement instead of if else.

this is the working if else statement

  private void RunScript(int a, int b, ref object A)
  {
    if (a < b)
    {
      Print("a is smaller than b");
      Print("b is bigger than a");
    }
    else if (a > b)
    {
      Print("a is bigger than b");
      Print("b is smaller than a");
    }
    else
    {
      Print("a equals b");
    }

this is the switch that I am trying to do

 private void RunScript(double a, double b, ref object A)
      {
        double whichIsBigger = a - b;
//below is the 58th line
        switch (whichIsBigger)
        {
          case whichIsBigger < 0:
            Print("a is bigger than b");
            break;
          case whichIsBigger > 0:
            Print("a is smaller than b");
            break;
          default:
            Print("a equals b");
            break;
        }

It gives me this Error (CS0151): A switch expression or case label must be a bool, char, string, integral, enum, or corresponding nullable type (line 58)

FYI, I'm trying to do this on rhinoceros3d, using the rhino common library.

and also, I've been trying to find a website or forum to learn c# where I can ask questions like these. I ended up here. I think that this kind of questions is pretty basic, but I can't find a resource that can give me an answer to this problem. I have read several posts and can't find a similar problem

If there are any sites where people can answer my questions fast like a chat room or something, please do let me know.

Answer 1

Basically, you're trying to run an evaluation in your case statement. You have to do the evaluation before, and use the values in your case statement.

If it's a true / false situation, you shouldn't use switch. Switch is generally for when there are a number of options that could be true. For example, if you had an enum with multiple values, and you want to do something different for each value (like DayOfWeek.Monday, DayOfWeek.Tuesday, etc). For the exact reason you're running into here.

If you really wanted, you could create an enum of ABCompare.Bigger, ABCompare.Smaller, ABCompare.Equal or something like that, and then switch on that -- but that doesn't really make sense.