The documentation uses is
in the example for “declaration patterns” but the book I am reading uses a switch statement. But when I try to run the code I run into errors.
using System;
public class Program
{
public static void Main()
{
var o = 42;
switch (o) {
case string s:
Console.WriteLine($"A piece of string is {s.Length} long");
break;
case int i:
Console.WriteLine($"That's numberwang! {i}");
break;
}
}
}
Error:
Compilation error (line 7, col 6): An expression of type 'int' cannot be handled by a pattern of type 'string'.
EDIT
Changing from
var o = 42;
to
object o = 42;
worked.
Full code: https://github.com/idg10/prog-cs-10-examples/blob/main/Ch02/BasicCoding/BasicCoding/Patterns.cs
The book uses a very specific scenario where
o
is an object that would accept any type. So using the object data type worked. Check the OP for the edit.