how can i find out the difference between two strings

using System;
using System.Linq;

namespace ConsoleApplication1
{
    class MyClass
    {
        static void Main(string[] args)
        {
            string separator =",";
            Console.WriteLine(Intersect("a,b,c,d,e", "b,e", separator));
        }

        private static string Intersect(string item1, string item2, string separator)
        {
            return string.Join(separator, item1.Where(item => !item2.Contains(item)));
        }
    }
}

a,c,d
Press any key to continue . . .

• String.Join[^]
  
• String.Contains[^]
  
• How does it work in C#? - Part 3 (C# Linq in detail)[^]
  

String result = nullstring
For each character in string2
    If character not in string1
        result += character
    End if
End For
Display result

string one = "a,b,c,d,e,u";
        string two = "b,e,z,t";
        int key=0;
        StringBuilder sb = new StringBuilder();

        string[] one_arr = one.Split(new char[] { ',' });
        string[] two_arr = two.Split(new char[] { ',' });

        foreach (string _one in one_arr)
        {
            key = 0;
            foreach (string _two in two_arr)
            {
                if (_one == _two)
                {
                    key = 1;
                }
            }
            if (key == 0)
            {
                sb.Append(_one + ",");
            }
        }
        foreach (string _two in two_arr)
        {
            key = 0;
            foreach (string _one in one_arr)
            {
                if (_one == _two)
                {
                    key = 1;
                }
            }
            if (key == 0)
            {
                sb.Append(_two + ",");
            }
        }
        Response.Write(sb);