using System;
using System.Text.RegularExpressions;
public class Program
{
public static void Main()
string[] patterns = {
// 0-9
"^[\\u0030-\\u0039]*$",
// A-Z
"^[\\u0041-\\u005A]*$",
// a-z
"^[\\u0061-\\u007A]*$",
// A-Za-z
"^[\\u0041-\\u005A\\u0061-\\u007A]*$",
// A-Za-z0-9
"^[\\u0041-\\u005A\\u0061-\\u007A\\u0030-\\u0039]*$",
};
string[] inputs = { "0493", "JAKE", "jake", "Jake", "J4k3", "Jæke" };
foreach (string pattern in patterns)
Console.WriteLine(pattern);
var re = new Regex(pattern);
foreach (string input in inputs)
var match = re.IsMatch(input);
var icon = match ? '✅' : '❌';
Console.Write($"{icon} {input}\t");
}
Console.WriteLine();
