**Course Title:** Mastering C#: From Fundamentals to Advanced Programming **Section Title:** File I/O and Serialization **Topic:** Working with file streams and binary data. **Introduction** In the previous topic, you learned how to read and write files in C#. Now, we will dive deeper into working with file streams and binary data. File streams allow you to read and write binary data to files, which is essential for working with image, audio, and video files. In this topic, you will learn how to work with file streams, binary data, and how to read and write binary files in C#. **Understanding File Streams** A file stream is a stream that read and writes files. Streams are an abstraction that allows you to read and write sequential data, such as text or binary data. File streams are a type of stream that specifically work with files. You can think of a file stream as a pointer to a file that you can use to read and write data to and from the file. **Working with FileStream Class** The `FileStream` class in C# provides methods and properties for reading and writing files. You can use this class to read and write text and binary data to files. The `FileStream` class inherits from the `Stream` class and provides additional functionality for working with files. Here is an example of how to use the `FileStream` class to read and write binary data to a file: ```csharp using System.IO; class Program { static void Main(string[] args) { // Create a file stream FileStream fileStream = new FileStream("example.bin", FileMode.Create); // Write binary data to the file byte[] binaryData = { 1, 2, 3, 4, 5 }; fileStream.Write(binaryData, 0, binaryData.Length); // Close the file stream fileStream.Close(); // Open the file for reading fileStream = new FileStream("example.bin", FileMode.Open); // Read the binary data from the file byte[] readData = new byte[binaryData.Length]; fileStream.Read(readData, 0, readData.Length); // Print the read data foreach (byte b in readData) { Console.Write(b + " "); } // Close the file stream fileStream.Close(); } } ``` **Working with BinaryReader and BinaryWriter Classes** The `BinaryReader` and `BinaryWriter` classes in C# provide methods for reading and writing binary data to streams. These classes are specifically designed for reading and writing binary data and provide methods for reading and writing primitive data types such as integers, strings, and booleans. Here is an example of how to use the `BinaryReader` and `BinaryWriter` classes to read and write binary data to a file: ```csharp using System.IO; class Program { static void Main(string[] args) { // Create a binary writer BinaryWriter binaryWriter = new BinaryWriter(new FileStream("example.bin", FileMode.Create)); // Write binary data to the file binaryWriter.Write(123); binaryWriter.Write("Hello, World!"); binaryWriter.Write(true); // Close the binary writer binaryWriter.Close(); // Create a binary reader BinaryReader binaryReader = new BinaryReader(new FileStream("example.bin", FileMode.Open)); // Read the binary data from the file int number = binaryReader.ReadInt32(); string str = binaryReader.ReadString(); bool boolean = binaryReader.ReadBoolean(); // Print the read data Console.WriteLine(number); Console.WriteLine(str); Console.WriteLine(boolean); // Close the binary reader binaryReader.Close(); } } ``` **Key Concepts** * File streams allow you to read and write binary data to files. * The `FileStream` class in C# provides methods and properties for reading and writing files. * The `BinaryReader` and `BinaryWriter` classes provide methods for reading and writing binary data to streams. **Practical Takeaways** * Use file streams to read and write binary data to files. * Use the `FileStream` class to read and write files. * Use the `BinaryReader` and `BinaryWriter` classes to read and write binary data to streams. **Additional Resources** * [MSDN Documentation for FileStream Class](https://docs.microsoft.com/en-us/dotnet/api/system.io.filestream) * [MSDN Documentation for BinaryReader Class](https://docs.microsoft.com/en-us/dotnet/api/system.io.binaryreader) * [MSDN Documentation for BinaryWriter Class](https://docs.microsoft.com/en-us/dotnet/api/system.io.binarywriter) **What's Next** In the next topic, we will cover introduction to serialization and deserialization (XML, JSON) in C#. You will learn how to serialize and deserialize objects to and from XML and JSON. **Leave a Comment or Ask a Question** Feel free to leave a comment or ask a question about this topic below. We will be happy to help you with any questions you may have. Please Note: There are no discussion boards for this course.