use std::slice::from_raw_parts;
use std::str::from_utf8_unchecked;

fn main() {
    let (p, len) = get_memory_str();
    let msg = read_memory_location(p, len);
    println!("The {} bytes at {:?} stored: {}", len, p, msg)
}

fn get_memory_str() -> (*const u8, usize) {
    // let str = "Hello world!";
    let str = "Hello world!".to_string();
    (str.as_ptr(), str.len())
}

fn read_memory_location(p: *const u8, len: usize) -> &'static str {
    unsafe { from_utf8_unchecked(from_raw_parts(p, len)) }
}

use anyhow::Result;
use std::io::{stdin, BufRead};
use std::slice::from_raw_parts;
use std::str::from_utf8_unchecked;

fn main() -> Result<()> {
    let (p, len) = read_user_input()?;
    let msg = read_memory((p, len));
    println!("The {} bytes at {:?} stored: {}", len, p, msg);
    Ok(())
}

type MyPoint = (*const u8, usize);

fn read_user_input() -> Result<MyPoint> {
    let mut user_input = String::new();
    let stdin = stdin();
    stdin.lock().read_line(&mut user_input)?;
    Ok(get_memory_location(&user_input))
}

fn get_memory_location(target: &String) -> MyPoint {
    (target.as_ptr(), target.len())
}

fn read_memory((p, len): MyPoint) -> &'static str {
    unsafe { from_utf8_unchecked(from_raw_parts(p, len)) }
}