Rust Programming Cookbook

How to do it...

Follow these steps to write more resilient programs:

1. Create a new project with cargo new resilient-programming and open it with VS Code.
2. Open src/main.rs to add a function:

use std::fs;use std::io;fn print_file_contents_qm(filename: &str) -> Result<(), io::Error> {    let contents = fs::read_to_string(filename)?;    println!("File contents, external fn: {:?}", contents);    Ok(())}

3. The preceding function prints the file contents if it finds the file; in addition to that, we have to call this function. For that, replace the existing main function with this:

fn main() -> Result<(), std::io::Error> {    println!("Ok: {:?}", print_file_contents_qm("testfile.txt"));    println!("Err: {:?}", print_file_contents_qm("not-a-file"));     let contents ...