using System;
using System.IO;

public class CopyApp {                              

  public static void Main(string[] args) {
    FileInfo inFile;
    do {                                            
        inFile = new FileInfo(args[0]);             
        if (!inFile.Exists)                         
          args[0] = "some other input file name";
    } while (!inFile.Exists);

    FileInfo outFile;
    do {                                               
        outFile = new FileInfo(args[1]);               
        if (outFile.Exists)                            
          args[1] = "some other output file name";
    } while (outFile.Exists);

    FileStream inStr   = inFile.OpenRead(),
               outStr  = outFile.OpenWrite();
    int c;
    do{
       c = inStr.ReadByte();
       if(c != -1) outStr.WriteByte((byte)c);
       if (StreamFull(outStr))                              
         DreamCommand("Fix some extra room on the disk");   
    } while (c != -1);  

    inStr.Close();
    if (!FileClosed(inStr))                                            
      DreamCommand("Deal with input file which cannot be closed");     

    outStr.Close();                                                    
    if (!FileClosed(outStr))                                           
      DreamCommand("Deal with output file which cannot be closed");
  }



  /* Programming pseudo commands for the sake of this example */

  public static void DreamCommand(string str){
    // Carry out the command str
  }

  public static bool FileClosed(Stream str){
    // Return if the stream str is closed
  }

  public static bool StreamFull(Stream str){
    // Return if the stream str is full
  }    

}

 
 
 
Pseudo program!
 
 
 
Repeatedly, query the user
for an appropriate file name of
an existing file.
 
 
 
 
Repeatedly, query the user
for an appropriate file of
a non-existing file.
 
 
 
 
 
 
 
 
 
If the disk is full attempt
to fix some more space.
 
 
 
If we cannot close the input file
deal with this problem.
 
If we cannot close the output file
deal with this problem.