[DotNetDevelopment] return in following code

[VIKAS GARG]

using System;
using System.IO;
class CopyFile
{
    public static void Main(string[] args)
    {
        int i;
        FileStream fin;
        FileStream fout;
        try
        {
            // open input file
            try
            {
                fin = new FileStream("abc.txt", FileMode.Open);
            }
            catch (FileNotFoundException exc)
            {
                Console.WriteLine(exc.Message + "\nInput File Not Found");
                return;
            }

            // open output file
            try
            {
                fout = new FileStream("xyz.txt", FileMode.Create);
            }
            catch (IOException exc)
            {
                Console.WriteLine(exc.Message + "\nError Opening Output
File");
                return;
            }
        }
        catch (IndexOutOfRangeException exc)
        {
            Console.WriteLine(exc);
            return;
        }
        //copy the file
        try {
            do {
                i = fin.ReadByte();
                if (i != -1) { fout.WriteByte((byte)i); }
            }
            while (i != -1);
        }
        catch (IOException exc)
        {
            Console.WriteLine(exc);
            return;
        }
        fin.Close();
        fout.Close();
    }
}




What is the use of return here in this progg
While writing the prog by mistake I had forgot to write return in this block
        catch (IndexOutOfRangeException exc)
        {
            Console.WriteLine(exc);
            return;
        }

After that my progg start giving me error that fin and fout are not
initialized
what return do in this kind of code