lifetimes

Author: monnetchr

src/main.rs

@@ -9,7 +9,8 @@ fn main() {
     basics::basics();
     println!();
     stuff::collections();
-    stuff::error_handling();
+    stuff::lifetimes();
     println!();
+    stuff::error_handling();
     guessgame::guess_game();
 }

src/myutils/stuff.rs

@@ -1,5 +1,6 @@
 use core::panic;
 use std::{
+    fmt::Display,
     fs::File,
     io::{ErrorKind, Read},
 };
@@ -32,3 +33,26 @@ fn read_username_from_file() -> Result<String, std::io::Error> {
     File::open("hello.txt")?.read_to_string(&mut s)?;
     Ok(s)
 }
+
+pub fn lifetimes() {
+    let string1 = String::from("long string is long");
+    {
+        let string2 = String::from("xyz");
+        let result = longest(string1.as_str(), string2.as_str());
+        println!("lifetimes: the longest string is {}", result);
+
+        longest_with_announcement(string1.as_str(), string2.as_str(), "hoho!");
+    }
+}
+
+fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
+    if x.len() > y.len() { x } else { y }
+}
+
+fn longest_with_announcement<'a, T>(x: &'a str, y: &'a str, ann: T) -> &'a str
+where
+    T: Display,
+{
+    println!("Announcement! {}", ann);
+    if x.len() > y.len() { x } else { y }
+}