Copy Source File to Destination File Using FileStream in C#

using System;
using System.IO;

class FileCopy
{
    // Main method to execute the file copying
    static void Main(string[] args)
    {
        // Prompt the user to enter the source file path
        Console.WriteLine("Please enter the source file path:");
        string sourcePath = Console.ReadLine();

        // Prompt the user to enter the destination file path
        Console.WriteLine("Please enter the destination file path:");
        string destPath = Console.ReadLine();

        // Check if the source file exists
        if (!File.Exists(sourcePath))
        {
            Console.WriteLine("The source file does not exist.");
            return; // Exit the program if the source file does not exist
        }

        // Check if the destination file already exists
        if (File.Exists(destPath))
        {
            Console.WriteLine("The destination file already exists.");
            Console.WriteLine("Do you want to overwrite it? (Y/N)");

            // Ask the user for confirmation to overwrite the file
            string overwriteConfirmation = Console.ReadLine().ToUpper();
            if (overwriteConfirmation != "Y")
            {
                Console.WriteLine("Operation cancelled. The destination file was not overwritten.");
                return; // Exit the program if the user does not want to overwrite
            }
        }

        try
        {
            // Open the source file with FileStream in read mode
            using (FileStream sourceStream = new FileStream(sourcePath, FileMode.Open, FileAccess.Read))
            {
                // Open the destination file with FileStream in write mode
                using (FileStream destStream = new FileStream(destPath, FileMode.Create, FileAccess.Write))
                {
                    // Define a buffer size of 512 KB
                    byte[] buffer = new byte[512 * 1024];

                    int bytesRead;
                    // Read the source file and write to the destination file in blocks of 512 KB
                    while ((bytesRead = sourceStream.Read(buffer, 0, buffer.Length)) > 0)
                    {
                        // Write the read block of data to the destination file
                        destStream.Write(buffer, 0, bytesRead);
                    }
                }
            }

            // Inform the user that the file has been copied successfully
            Console.WriteLine("File copied successfully!");
        }
        catch (Exception ex)
        {
            // Handle any errors that occur during the file copy process
            Console.WriteLine("An error occurred during the file copy process: " + ex.Message);
        }
    }
}

 Output

//Assuming the user runs the program and inputs the following paths:
Please enter the source file path:
C:\path\to\source\file.txt
Please enter the destination file path:
D:\path\to\destination\file2.txt

//If the source file exists and the destination does not already exist, the program will output:
File copied successfully!

//If the destination file already exists, the program will prompt:
The destination file already exists.
Do you want to overwrite it? (Y/N)

//If the user chooses 'Y', the program will proceed to copy the file, and the following message will be displayed:
File copied successfully!

//If the user chooses 'N', the program will output:
Operation cancelled. The destination file was not overwritten.