0

I'm writing several nested switch statements with quite a few cases in some spots.

I'm trying to figure out a way to create a list of cases to then be referenced in later switch statements.

Is there a way to do this?

It would certainly clean up my code.

For example, I have four separate cases for a "yes" answer.

I am looking for a way to store these four cases in a variable and call on that variable each time I want to use them in a switch.

Console.Write("\nWere you feeling exhausted? ");
response = Console.ReadLine().ToLower();
Console.Clear();
switch (response)
{
    case "yes":
    case "y":
    case "yep":
    case "yeah":
        {
            goto ThreeTwo;
        }
    case "no":
    case "n":
    case "nope":
    case "nah":
labmate
  • 37
  • 4

2 Answers2

4

A nice clean way to do this is first to declare an enum to represent the answer values. It will need "Yes", "No" and "Undefined" (the latter to represent an answer which is neither "Yes" nor "No"):

public enum YesOrNo
{
    Undefined,
    Yes,
    No
}

Then you can wrap the yes/no detection logic in a class. There are many ways to do this; here's a simple one (you could use a dictionary instead, but for such a small number of strings it's not really necessary, and I'm trying to keep this as simple as possible):

public static class YesOrNoDetector
{
    static readonly string[] _yesAnswers = { "yes", "y", "yep", "yeah", "affirmative" };
    static readonly string[] _noAnswers  = { "no",  "n", "nah", "nope", "negative"    };

    public static YesOrNo Detect(string answer)
    {
        if (_yesAnswers.Contains(answer.ToLower()))
            return YesOrNo.Yes;

        if (_noAnswers.Contains(answer.ToLower()))
            return YesOrNo.No;

        return YesOrNo.Undefined;
    }
}

(Note how it also handles uppercase answers by converting the string to lowercase before comparing.)

Then your original code becomes something like:

switch (YesOrNoDetector.Detect(response))
{
    case YesOrNo.Yes:
    {
        goto ThreeTwo;  // Please get rid of this goto!
    }

    case YesOrNo.No:
    {
        // Handle "No".
        break;
    }

    case YesOrNo.Undefined:
    {
        // Handle incorrect answer.
        break;
    }
}
Matthew Watson
  • 104,400
  • 10
  • 158
  • 276
  • 1
    Beat me to it, and; even makes use of the switch :-) – Stefan Aug 17 '21 at 08:13
  • 1
    Beat me as well, by about five seconds! Maybe StackOverflow needs some kind of "I'm working on an answer" button. – Robson Aug 17 '21 at 08:13
  • 1
    Yeah, happens to all of us. :) Sometimes I think it encourages quick and sloppy answers that the answerer edits after posting, which isn't really ideal - but I've never been able to think of a good solution. – Matthew Watson Aug 17 '21 at 08:14
  • 1
    Thank you so much for this answer, it worked perfectly! And now I have to ask: why are goto's so universally hated and what would be a good alternative for them. Thanks again! :^) – labmate Aug 17 '21 at 20:41
  • @labmate Sometimes a `goto` can be useful, but often they can make the code harder to follow and more error-prone. There's [some discussion about the topic here](https://stackoverflow.com/questions/46586/goto-still-considered-harmful#:~:text=Every%20control%20structure%20can%20be%20implemented%20in%20terms,and%20these%20have%20been%20eliminated%20by%20structured%20programming.) that you might find interesting. In your case, you might want to put the code in a method and call it, but it's hard to say without context. – Matthew Watson Aug 18 '21 at 07:53
  • Really nice answer :-) Really wanted to give +100 for **// Please get rid of this goto!** :-) – nIcE cOw Aug 23 '21 at 14:28
2

Having this enum:

public enum Answers
{
  Other,
  Yes,
  No
}

Any expected possibility can be added.

Also several enums can be created for various use cases.

Here Other means not defined, not predicted, unknown, etc.

We can define this allotment/distribution/dispatch table:

using System;
using System.Collections.Generic;

readonly Dictionary<Answers, List<string>> AcceptedAnswers
  = new Dictionary<Answers, List<string>>
  {
    { Answers.Yes, new List<string> { "yes", "y", "yep", "yeah" } },
    { Answers.No, new List<string> { "no", "n", "nope", "nah" } }
  };

Thus we can easily define synonyms for each enum value.

And we'll use it by defining this verification method:

Answers GetAnswer(string input)
{
  foreach ( Answers item in Enum.GetValues(typeof(Answers)) )
    if ( AcceptedAnswers.ContainsKey(item) )
      if ( AcceptedAnswers[item].Contains(input) )
        return item;
  return Answers.Other;
}

Test

Console.WriteLine("Do you agree?");
var answer = GetAnswer(Console.ReadLine());
Console.WriteLine();
Console.WriteLine($"Your answer is: {answer}.");

Output

Do you agree?
yep

Your answer is: Yes.

Advanced usage

bool retry;
do
{
  retry = false;
  Console.WriteLine("Do you agree?");
  var answer = GetAnswer(Console.ReadLine());
  Console.WriteLine();
  Console.WriteLine($"Your answer is: {answer}.");
  switch ( answer )
  {
    case Answers.Yes:
      // ...
      break;
    case Answers.No:
      // ...
      break;
    default:
      Console.WriteLine();
      Console.WriteLine("I don't understand :(");
      Console.WriteLine();
      retry = true;
      break;
  }
}
while ( retry );

Do you agree?
I don't know

Your answer is: Other.

I don't understand :(

Do you agree?
yeah

Your answer is: Yes.

Please do not use goto more than once per century.

How to resolve this compilation error "Using unassigned local variable 'hak'" when using goto?