find the size of a file in rust

To get the size of a file in Rust, we can use the metadata method provided by the std::fs module. This method returns a Result that contains the file's metadata, which includes information about the file's size, type, and creation/modification times.

Here's an example code that gets the size of a file:

main.rs
use std::fs;

fn main() -> std::io::Result<()> {
    let metadata = fs::metadata("path/to/file")?;
    let size = metadata.len();
    println!("The file size is {} bytes", size);
    Ok(())
}
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In this code, we first import the fs module, which provides file-system related functionality, and then call the metadata method with the path to the file we're interested in. This method returns a Result that contains the file's metadata if the operation was successful, or an error if it failed for some reason.

If the metadata was successfully retrieved, we can then access the file's size by calling the len method on the metadata object. This method returns the file's size in bytes.

Finally, we print out the size of the file to the console. Note that we've used the ? operator several times in this code to propagate any errors that might occur while reading the metadata. This is a convenient way to handle errors in Rust without having to write lots of boilerplate error-handling code.