Rust learning: lessons, notes, and exercise crates

learn-panic/.gitignore

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+/target

learn-panic/Cargo.lock

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+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "learn-panic"
+version = "0.1.0"

learn-panic/Cargo.toml

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+[package]
+name = "learn-panic"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]

learn-panic/hello.txt

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+alkdsfjlkafdsj

learn-panic/src/main.rs

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+use std::{fs::File, io::ErrorKind, panic};
+fn main() {
+    let _v = vec![1, 2, 3];
+
+    let greeting_file_result = File::open("hello.txt");
+
+    let _greeting_file = match greeting_file_result {
+        Ok(file) => file,
+        Err(error) => match error.kind() {
+            ErrorKind::NotFound => match File::create("hello.txt") {
+                Ok(fc) => fc,
+                Err(e) => panic!("Problem creating the file: {e}"),
+            },
+            _ => {
+                panic!("Problem opening the file: {error:?}");
+            }
+        },
+    };
+
+    // v[99];
+}
+
+use std::io::{self, Read};
+
+fn read_username_from_file() -> Result<String, io::Error> {
+    let mut username_file = File::open("hello.txt")?;
+    let mut username = String::new();
+    username_file.read_to_string(&mut username)?;
+    Ok(username)
+}