File Input and Output

Read from and write to text files using the standard library.

Learning objectives

• Write text to a file
• Read text from a file
• Handle file errors with Result

Writing Files

Rust’s standard library includes tools for file operations. For simple cases, std::fs::write can write text into a file.

Reading Files

std::fs::read_to_string can read a text file into a String.

Practical Use

File input and output are useful for reports, logs, configuration files, and small data storage tasks.

Example code

use std::fs;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    fs::write("notes.txt", "Learning Rust step by step")?;

    let content = fs::read_to_string("notes.txt")?;
    println!("File content: {}", content);

    Ok(())
}