From f23a4fe4bcb7ae0b47d625f89abb281646ea33a7 Mon Sep 17 00:00:00 2001
From: Jordan Gong <jordan.gong@protonmail.com>
Date: Thu, 3 Sep 2020 15:26:30 +0800
Subject: Care about lifetimes

---
 lifetimes/.gitignore  | 18 ++++++++++++++++++
 lifetimes/Cargo.toml  |  9 +++++++++
 lifetimes/src/main.rs | 41 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 68 insertions(+)
 create mode 100644 lifetimes/.gitignore
 create mode 100644 lifetimes/Cargo.toml
 create mode 100644 lifetimes/src/main.rs

diff --git a/lifetimes/.gitignore b/lifetimes/.gitignore
new file mode 100644
index 0000000..e629269
--- /dev/null
+++ b/lifetimes/.gitignore
@@ -0,0 +1,18 @@
+
+# Created by https://www.toptal.com/developers/gitignore/api/rust
+# Edit at https://www.toptal.com/developers/gitignore?templates=rust
+
+### Rust ###
+# Generated by Cargo
+# will have compiled files and executables
+/target/
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
+Cargo.lock
+
+# These are backup files generated by rustfmt
+**/*.rs.bk
+
+# End of https://www.toptal.com/developers/gitignore/api/rust
+
diff --git a/lifetimes/Cargo.toml b/lifetimes/Cargo.toml
new file mode 100644
index 0000000..3655444
--- /dev/null
+++ b/lifetimes/Cargo.toml
@@ -0,0 +1,9 @@
+[package]
+name = "lifetimes"
+version = "0.1.0"
+authors = ["Jordan Gong <jordan.gong@protonmail.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/lifetimes/src/main.rs b/lifetimes/src/main.rs
new file mode 100644
index 0000000..8dec31f
--- /dev/null
+++ b/lifetimes/src/main.rs
@@ -0,0 +1,41 @@
+fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
+    if x.len() > y.len() {
+        x
+    } else {
+        y
+    }
+}
+
+use std::fmt::Display;
+
+// generic type params, trait bound, and lifetimes
+fn longest_with_an_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
+    }
+}
+
+fn main() {
+    let string1 = String::from("abcd");
+    let string2 = "xyz";
+
+    let result = longest(string1.as_str(), string2);
+    println!("The longest string is {}", result);
+
+    let result = longest_with_an_announcement(
+        string1.as_str(),
+        string2,
+        "Today is someone's birthday!",
+    );
+    println!("The longest string is {}", result);
+}
-- 
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