//Anagram Check: Check if two strings are anagrams of each other.

using System;

using System.Linq;

using System.Text.RegularExpressions;

​

public class Program

{

    public static void Main()

    {

        while (true)

        {

            Console.WriteLine("Anagram check: provide 2 words or q to quit:");

            var input = Console.ReadLine();

            if (input.Length == 0)

            {

                Console.WriteLine($"Error; You need to provide 2 words.");

                continue;

            };  

            if (input.ToLower() == "q") break;

​

            string[] words = Regex.Split(input, @"[^a-zA-Z]+");

            if (words.Length < 2)

            {

                Console.WriteLine($"Error; You need to provide 2 words.");

                continue;

            }

            Console.WriteLine($"Is word <{words[0]}> an anagram for word <{words[1]}>: {IsAnagram(words[0].ToLower(), words[1].ToLower())}");

        }

    }

​

    private static bool IsAnagram(string w1, string w2)

    {

        if (w1.Length != w2.Length) return false;

​

        var frequency1 = new int[30];

        var frequency2 = new int[30];

​

        foreach (var letter in w1)

            frequency1[letter - 'a']++;

        foreach (var letter in w2)

            frequency2[letter - 'a']++;

​

        return frequency1.SequenceEqual(frequency2);

    }

}