use std::error::Error;
use std::fs::File;
use std::io::{Read, Seek, SeekFrom, Write};
pub fn read(file: &mut File) -> Result<f64, Box<dyn Error>> {
let mut content = String::new();
file.read_to_string(&mut content)?;
file.seek(SeekFrom::Start(0))?;
Ok(content.trim().parse()?)
}
pub fn write(file: &mut File, value: f64) -> Result<(), Box<dyn Error>> {
file.write_all(value.to_string().as_bytes())?;
file.seek(SeekFrom::Start(0))?;
Ok(())
}