MCQs on File I/O and Streams | C#
This collection of 30 multiple-choice questions (MCQs) focuses on essential concepts of File I/O, Streams, and Serialization in C#. It covers topics like file reading and writing, directory operations, and stream handling. These MCQs are designed to test your understanding of C# file handling, including StreamReader, StreamWriter, and serialization techniques.
1. File I/O and Streams
- Which class in C# is used to read characters from a file?
- A) FileReader
- B) FileStream
- C) StreamReader
- D) StreamWriter
- Which method is used to write text to a file in C#?
- A) WriteToFile
- B) Write
- C) WriteLine
- D) StreamWriter.Write
- What type of stream is used for reading binary data from a file?
- A) FileStream
- B) MemoryStream
- C) BinaryReader
- D) TextReader
- To read a line from a file, which method of StreamReader is used?
- A) ReadToEnd
- B) ReadLine
- C) ReadByte
- D) ReadChar
- Which method allows reading all bytes from a file at once in C#?
- A) ReadAllBytes
- B) ReadFile
- C) ReadBytes
- D) File.Read
2. File Streams
- What does FileStream allow you to do?
- A) Write data to a memory stream
- B) Open, read, and write to a file
- C) Compress file data
- D) Serialize objects
- What is the default file access mode for a FileStream?
- A) ReadWrite
- B) WriteOnly
- C) Read
- D) Append
- Which method in FileStream writes data to a file?
- A) WriteBytes
- B) Write
- C) Flush
- D) Close
- What is the purpose of the FileStream.Position property?
- A) To specify the buffer size
- B) To get or set the current position in the file
- C) To check if the file exists
- D) To read the next byte in the stream
- Which of the following classes is not derived from Stream?
- A) MemoryStream
- B) FileStream
- C) StreamReader
- D) StringWriter
3. Directory and Path Operations
- Which class in C# allows you to manipulate file and directory paths?
- A) Path
- B) File
- C) DirectoryInfo
- D) FileInfo
- How can you create a directory in C# if it doesn’t already exist?
- A) Directory.Create
- B) Directory.CreateDirectory
- C) File.CreateDirectory
- D) Path.Create
- What is the purpose of Directory.Exists method?
- A) To check if a directory is writable
- B) To check if a directory exists
- C) To check the contents of a directory
- D) To list files in a directory
- Which method in the Path class is used to combine two paths into one?
- A) Path.Combine
- B) Path.Add
- C) Path.Merge
- D) Path.Join
- To get the file extension from a path, which method is used?
- A) Path.GetFileExtension
- B) Path.GetExtension
- C) Path.GetName
- D) Path.GetFileName
4. StreamReader and StreamWriter Classes
- Which of the following is a correct way to instantiate a StreamWriter?
- A) StreamWriter writer = new StreamWriter();
- B) StreamWriter writer = new StreamWriter(“file.txt”);
- C) StreamWriter writer = new StreamWriter(File.Open(“file.txt”));
- D) Both B and C
- In StreamReader, which method is used to read all content from a file?
- A) ReadAllBytes
- B) Read
- C) ReadLine
- D) ReadToEnd
- What is the default encoding used by StreamWriter in C#?
- A) UTF-8
- B) ASCII
- C) Unicode
- D) UTF-16
- Which method in StreamWriter is used to write a line of text to a file?
- A) WriteLine
- B) Write
- C) WriteText
- D) WriteString
- How do you close a StreamReader or StreamWriter in C#?
- A) Close()
- B) Dispose()
- C) Both A and B
- D) None of the above
5. Serialization and Deserialization
- Which attribute marks a class for serialization in C#?
- A) [Serializable]
- B) [DataContract]
- C) [SerializableClass]
- D) [DataMember]
- What is deserialization in C#?
- A) Converting an object to a byte stream
- B) Converting a byte stream back to an object
- C) Saving an object to a file
- D) Encrypting object data
- Which method is used to deserialize an object from a file in C#?
- A) Deserialize()
- B) DeserializeObject()
- C) BinaryFormatter.Deserialize()
- D) File.Deserialize()
- Which of the following is true about the BinaryFormatter class?
- A) It is used for encrypting objects.
- B) It supports object serialization and deserialization.
- C) It can only serialize primitive types.
- D) It is deprecated and not recommended for use.
- What does the XmlSerializer class do in C#?
- A) Serializes objects into binary format
- B) Serializes objects into XML format
- C) Decrypts serialized objects
- D) Writes data to files in XML
- What is the role of the [NonSerialized] attribute?
- A) It marks the class as non-serializable
- B) It marks a property or field as not to be serialized
- C) It indicates a class cannot be deserialized
- D) It is used to encrypt fields during serialization
- Which stream is typically used for binary serialization?
- A) FileStream
- B) MemoryStream
- C) NetworkStream
- D) BinaryWriter
- Which of these formats is used by the BinaryFormatter for serialization?
- A) XML
- B) JSON
- C) Binary
- D) Text
- How can you deserialize an object from a MemoryStream?
- A) MemoryStream.Deserialize()
- B) BinaryFormatter.Deserialize()
- C) StreamReader.ReadObject()
- D) FileStream.DeserializeObject()
- Which of these classes cannot be used for serialization in C#?
- A) BinaryFormatter
- B) SoapFormatter
- C) XmlSerializer
- D) FileStream
Answer Key
| Qno | Answer (Option with Text) |
|---|---|
| 1 | C) StreamReader |
| 2 | B) Write |
| 3 | A) FileStream |
| 4 | B) ReadLine |
| 5 | A) ReadAllBytes |
| 6 | B) Open, read, and write to a file |
| 7 | C) Read |
| 8 | B) Write |
| 9 | B) To get or set the current position in the file |
| 10 | D) StringWriter |
| 11 | A) Path |
| 12 | B) Directory.CreateDirectory |
| 13 | B) To check if a directory exists |
| 14 | A) Path.Combine |
| 15 | B) Path.GetExtension |
| 16 | D) Both B and C |
| 17 | D) ReadToEnd |
| 18 | A) UTF-8 |
| 19 | A) WriteLine |
| 20 | C) Both A and B |
| 21 | A) [Serializable] |
| 22 | B) Converting a byte stream back to an object |
| 23 | C) BinaryFormatter.Deserialize() |
| 24 | B) It supports object serialization and deserialization |
| 25 | B) Serializes objects into XML format |
| 26 | B) It marks a property or field as not to be serialized |
| 27 | A) FileStream |
| 28 | C) Binary |
| 29 | B) BinaryFormatter.Deserialize() |
| 30 | D) FileStream |