https://sharplab.io/#gist:9f2a8f6829a8334b318f2718be780b80

String switches can be wild.cs

using System;
public class C {
    public Int32 First(string Command, Int32 A, Int32 B) {
        switch(Command) {
            case "Add":
                return A + B;
                
            case "Substract":
                return A - B;
                
            case "Divide":
                return A / B;
                
            case "Multiply":
                return A * B;
                
            default:
                return -1;
        }
    }

    public Int32 Second(string Command, Int32 A, Int32 B) {
        switch(Command) {
            case "Add":
                return A + B;
                
            case "Substract":
                return A - B;
                
            case "Divide":
                return A / B;
                
            case "Multiply":
                return A * B;

            case "A":
            case "B":
            case "C":
            case "D":                
            default:
                return -1;
        }
    }
}

​String switches can be wild.decompiled.cs

using System.Diagnostics;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Security;
using System.Security.Permissions;

[assembly: CompilationRelaxations(8)]
[assembly: RuntimeCompatibility(WrapNonExceptionThrows = true)]
[assembly: Debuggable(DebuggableAttribute.DebuggingModes.IgnoreSymbolStoreSequencePoints)]
[assembly: SecurityPermission(SecurityAction.RequestMinimum, SkipVerification = true)]
[assembly: AssemblyVersion("0.0.0.0")]
[module: UnverifiableCode]
public class C
{
    public int First(string Command, int A, int B)
    {
        if (!(Command == "Add"))
        {
            if (!(Command == "Substract"))
            {
                if (!(Command == "Divide"))
                {
                    if (Command == "Multiply")
                    {
                        return A * B;
                    }
                    return -1;
                }
                return A / B;
            }
            return A - B;
        }
        return A + B;
    }

    public int Second(string Command, int A, int B)
    {
        uint num = <PrivateImplementationDetails>.ComputeStringHash(Command);
        if (num <= 2805258597u)
        {
            if (num <= 2103908752)
            {
                if (num != 916994956)
                {
                    if (num == 2103908752 && Command == "Divide")
                    {
                        return A / B;
                    }
                }
                else if (Command == "Substract")
                {
                    return A - B;
                }
            }
            else if (num != 2646845972u)
            {
                if (num == 2805258597u && Command == "Multiply")
                {
                    return A * B;
                }
            }
            else if (Command == "Add")
            {
                return A + B;
            }
        }
        else if (num <= 3289118412u)
        {
            if (num != 3238785555u)
            {
                if (num == 3289118412u && Command == "A")
                {
                }
            }
            else if (Command == "D")
            {
            }
        }
        else if (num != 3322673650u)
        {
            if (num == 3339451269u && Command == "B")
            {
            }
        }
        else if (Command == "C")
        {
        }
        return -1;
    }
}
[CompilerGenerated]
internal sealed class <PrivateImplementationDetails>
{
    internal static uint ComputeStringHash(string s)
    {
        uint num = default(uint);
        if (s != null)
        {
            num = 2166136261u;
            int num2 = 0;
            while (num2 < s.Length)
            {
                num = (s[num2] ^ num) * 16777619;
                num2++;
            }
        }
        return num;
    }
}

​​.sharplab.json

{
    "version": 1,
    "target": "C#",
    "mode": "Release",
    "branch": "master"
}