Listing05.15.PassingCommandLineArgumentsToMain.cs

namespace AddisonWesley.Michaelis.EssentialCSharp.Chapter05.Listing05_15;

#region INCLUDE
public class Program
{
    #region HIGHLIGHT
    public static int Main(string[] args)
    #endregion HIGHLIGHT
    {
        #region HIGHLIGHT
        int result;
        if(args?.Length != 2 )
        #endregion HIGHLIGHT
        {
            // Exactly two arguments must be specified; give an error
            Console.WriteLine(
                "ERROR:  You must specify the "
                + "URL and the file name");
            Console.WriteLine(
                "Usage: Downloader.exe <URL> <TargetFileName>");
            result = 1;
        }
        else
        {
            #region HIGHLIGHT
            string urlString = args[0];
            string fileName = args[1];
            #endregion HIGHLIGHT
            HttpClient client = new();
            byte[] response =
                client.GetByteArrayAsync(urlString).Result;
            client.Dispose();
            File.WriteAllBytes(fileName, response);
            Console.WriteLine($"Downloaded '{ fileName }' from '{ urlString }'.");
            result = 0;
        }
        #region HIGHLIGHT
        return result;
        #endregion HIGHLIGHT
    }
}
#endregion INCLUDE