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Adds three new exercises under exercises/24_file_io/, as proposed in rust-lang/rustlings#2233: - file_io1: read a whole file with fs::read_to_string and handle the Result. - file_io2: read/write a file efficiently with BufReader/BufWriter. - file_io3: build a path with PathBuf and inspect it with .metadata(). Includes matching solutions and a README describing the learning goal of each exercise.
31 lines
1.4 KiB
Markdown
31 lines
1.4 KiB
Markdown
# File IO
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Rust provides several file I/O functions in the standard library. Buffered
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reads and writes provide better performance by reducing the number of
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underlying system calls.
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## Learning goals
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- **file_io1** — Read an entire file into memory with `fs::read_to_string`
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and handle the `Result` it returns instead of unwrapping blindly, so you
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get comfortable with the basic "open, read, handle the error" pattern
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that most file I/O in Rust builds on.
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- **file_io2** — Wrap a `File` in a `BufReader` to read it line by line and
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a `BufWriter` to write the transformed output, so you understand why
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buffering matters for I/O performance and how `BufRead::lines` lets you
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process input incrementally instead of loading it all at once.
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- **file_io3** — Build a path with `PathBuf`, then call `.metadata()` to
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inspect properties like creation time, size, and permissions, so you can
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work with the filesystem safely across platforms without hardcoding
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path separators.
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## Further information
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Here is the documentation for these functions in the standard library.
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- [read_to_string](https://doc.rust-lang.org/std/fs/fn.read_to_string.html)
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- [BufReader](https://doc.rust-lang.org/std/io/struct.BufReader.html)
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- [BufWriter](https://doc.rust-lang.org/std/io/struct.BufWriter.html)
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- [Path](https://doc.rust-lang.org/stable/std/path/struct.Path.html)
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- [PathBuf](https://doc.rust-lang.org/std/path/struct.PathBuf.html)
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