8.7. Preview Questions#
Complete these questions before class to prepare for the chapter. Use the dropdowns to check your answers.
8.7.1. True or False#
1. StreamReader is used to write data to a file.
Answer
False — StreamReader reads; use StreamWriter to write.
2. You should close a file stream after you are done using it.
Answer
True — Unclosed streams can cause resource leaks or data loss.
3. File.ReadAllText() reads the entire file into a single string.
Answer
True — It returns all file content as one string.
4. Regular expressions can only match exact strings, not patterns.
Answer
False — Regex is designed to match patterns, not just literal strings.
5. The using statement ensures a resource is disposed when the block exits.
Answer
True — using calls Dispose() automatically, even on exceptions.
8.7.2. Multiple Choice#
1. Which C# class reads text line by line from a file?
a) FileWriter
b) StreamReader
c) FileInput
d) TextGetter
Answer
b) StreamReader — StreamReader wraps a file and exposes ReadLine() and ReadToEnd().
2. Which namespace contains file I/O classes in C#?
a) System.IO
b) System.File
c) System.Text
d) System.Storage
Answer
a) System.IO — System.IO contains StreamReader, StreamWriter, File, etc.
3. What does StreamWriter.WriteLine(text) do?
a) Reads a line
b) Writes text followed by a newline
c) Deletes a line
d) Counts lines in a file
Answer
b) Writes text followed by a newline — It writes the string and appends the platform’s newline character.
4. What does File.Exists(path) return if the file is not found?
a) null
b) 0
c) false
d) throws an exception
Answer
c) false — File.Exists() returns false for missing files — it never throws.
5. In a regular expression, what does the pattern \d+ match?
a) Any letter
b) One or more digits
c) Whitespace
d) Any character
Answer
b) One or more digits — \d matches a digit; + means one or more.
Footnotes