using System;

​

public class Program

{

    public static void Main(String s)

    {

        // referenced

        // https://docs.microsoft.com/en-us/dotnet/api/system.string.contains?view=net-6.0

        /// https://www.w3schools.com/cs/cs_switch.php

        // testing: 

        //string input = "<xmlInput>";

        //string input = "<xmlInput";

        //string input = "xmlInput>";

        string input = "xmlInput";

        string b1 = "<";

        string b2 = ">";

        int statusCode = 0;

        bool bool1 = input.Contains(b1);

        bool bool2 = input.Contains(b2);

        if (bool1 && bool2)

        {

            statusCode = 1;

        }

        else if (bool1 || bool2)

        {

            statusCode = 2;

        }

        else

        {

            statusCode = 3;

        }

​

        switch (statusCode)

        {

            case 1:

                Console.WriteLine("well-formed XML");

                break;

            case 2:

                Console.WriteLine("Error...");

                break;

            case 3:

                Console.WriteLine("null");

                break;

        }

    }

}