using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.IO;

namespace ConsoleApplication1

{

    class Program

    {

        static void Main(string[] args)

        {

            string s,t;

            string[] c;

            StreamReader f1 = new StreamReader("C:\\Users\\elev\\Desktop\\Visual\\unu.txt");

            StreamReader f2 = new StreamReader("C:\\Users\\elev\\Desktop\\Visual\\doi.txt");

            StreamWriter f3 = new StreamWriter("C:\\Users\\elev\\Desktop\\Visual\\trei.txt");

            t = null;

            s = f1.ReadLine(); t = t + s+" ";

            while (!f1.EndOfStream) { s = f1.ReadLine(); t = t + s+" "; }

            s = f2.ReadLine(); t = t + s+" ";

          while (!f2.EndOfStream) {s = f2.ReadLine(); t=t+s+" ";}

             c = t.Split(' ');

             foreach (string x in c)

                 f3.WriteLine(x);

            f1.Close();

                 f2.Close();

                 f3.Close()

                     ;

        }

    }

}

​