Care about lifetimes

3 files changed, 68 insertions, 0 deletions

diff --git a/lifetimes/.gitignore b/lifetimes/.gitignore
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+
+# 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
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+++ b/lifetimes/Cargo.toml
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+[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
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+++ b/lifetimes/src/main.rs
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+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);
+}