rust_ex10.rs

fn search<'a, 'b>(needle: &'a str, haystack: &'b str) -> Option<&'b str> {
    // imagine some clever algorithm here
    // that returns a slice of the original string
    let len = needle.len();
    if haystack.chars().nth(0) == needle.chars().nth(0) {
        Some(&haystack[..len])
    } else if haystack.chars().nth(1) == needle.chars().nth(0) {
        Some(&haystack[1..len+1])
    } else {
        None
    }
}

fn main() {
    let haystack = "hello little girl";
    let res;
    {
        let needle = String::from("ello");
        res = search(&needle, haystack);
    }
    match res {
        Some(x) => println!("found {}", x),
        None => println!("nothing found")
    }
    // outputs "found ello"
}