using System;

using System.Collections.Generic;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        var search = "C";

        var pattern = @$"({search})";

        Console.WriteLine(pattern);

        var persons = Persons.GetAll();

        var results = new List<Person>();

        foreach (var person in persons)

        {

            if (Regex.IsMatch(person.Name, pattern, RegexOptions.IgnoreCase))

            {

                results.Add(person);

            }

            if (Regex.IsMatch(person.Surname, pattern, RegexOptions.IgnoreCase))

            {

                results.Add(person);

            }

        }

        Console.WriteLine("Search results:");

        Console.WriteLine("----------------");

        foreach (var item in results)

        {

            Console.WriteLine($"{item.Name} {item.Surname}");

        }

    }

}

​

public class Person

{

    public string Name { get; set; }

    public string Surname { get; set; }

}

​

public static class Persons

{

    public static List<Person> GetAll()

    {

        var people = new List<Person>{

            new Person { Name = "Paul", Surname = "Cook" },

            new Person { Name = "Dade", Surname = "Murphey" },

            new Person { Name = "Kate", Surname = "Libby" },

            new Person { Name = "Emmanuel", Surname = "Goldstein" },

            new Person { Name = "Eugene", Surname = "Belford" },

            new Person { Name = "Ramon", Surname = "Sanchez" },

            new Person { Name = "Joey", Surname = "Pardella" },

            new Person { Name = "Lauren", Surname = "Murphey" }

        };

        return people;

    }

}