concepts: rustfmt

[learn-rust.git] / src / main.rs

diff --git a/src/main.rs b/src/main.rs
deleted file mode 100644 (file)
index c07c405..0000000
--- a/src/main.rs
+++ /dev/null
@@ -1,124 +0,0 @@
-mod word_utils;
-
-use std::collections::HashMap;
-use std::io::{prelude::*, ErrorKind};
-use std::fs::{self, File};
-
-use word_utils::{first_word, second_word};
-
-fn test_strings() {
-    let s = String::from("Hello world");
-    println!("first word: '{}'", first_word(&s));
-    println!("second word: '{}'", second_word(&s).unwrap());
-
-    let s2 = "hello dude blah";
-    println!("second word of single: '{}'", second_word(s2).unwrap_or("(none)"));
-
-    match second_word(s2) {
-        Some(w) => println!("match: second word of '{}' exists: {}", s2, w),
-        None => println!("match: second word of '{}' does not exist", s2),
-    }
-}
-
-fn test_vectors() {
-    let v1 = vec![1, 2, 3];
-    println!("statically initialized vector: {:?}", v1);
-
-    let mut v2: Vec<String> = Vec::new();
-    v2.push("Hello".to_string());
-    v2.push(String::from("world"));
-    println!("dynamically built vector: {:?}", v2);
-    println!("first element: {}", v2[0]);
-    for el in &mut v2 {
-        *el += "xx";
-    }
-    for el in &v2 {
-        println!("{}", el);
-    }
-}
-
-fn test_hashmaps() {
-    let mut scores = HashMap::new();
-    scores.insert("john", 10);
-    scores.insert("mary", 20);
-
-    println!("scores: {:?}", scores);
-
-    // hash map with .collect()
-    let persons = vec![("homer", 42), ("marge", 30)];
-    let collect_scores: HashMap<_, _> = persons.into_iter().collect();
-    println!("collect_scores: {:?}", collect_scores);
-
-    for (p, s) in &collect_scores {
-        println!("person {}: score {}", p, s);
-    }
-
-    println!("john's score: {}", scores.get("john").unwrap());
-    println!("jake's score: {}", scores.get("jake").unwrap_or(&-1));
-
-    // double scores
-    for (_, v) in scores.iter_mut() {
-        *v *= 2;
-    }
-    println!("scores after doubling: {:?}", scores);
-
-    // double scores of immutable hashmap (rebuild it)
-    let collect_scores: HashMap<_, _> = collect_scores.iter()
-        .map(|(k, v)| (k, 2 * v))
-        .collect();
-    println!("collect_scores after rebuilding with doubling: {:?}", collect_scores);
-}
-
-fn read_file(path: &str) -> Result<String, std::io::Error> {
-    let mut s = String::new();
-    File::open(path)?
-        .read_to_string(&mut s)?;
-    Ok(s)
-}
-
-fn test_files() {
-    if let Ok(mut f) = File::open("Cargo.toml") {
-        let mut contents = String::new();
-        match f.read_to_string(&mut contents) {
-            Ok(len) => println!("successfully opened Cargo.toml: {:?}, contents {} bytes:\n{}\n----------", f, len, contents),
-            Err(e) => panic!("could not read file: {:?}", e)
-        }
-    } else {
-        println!("could not open Cargo.toml");
-    }
-
-    // alternative form, more specific error checking
-    let mut f = File::open("Cargo.toml").unwrap_or_else(|e| {
-        if e.kind() == ErrorKind::NotFound {
-            println!("Cargo.toml not found, falling back to /dev/null");
-            // need to return a File
-            File::open("/dev/null").unwrap()
-        } else {
-            panic!("Could not open Cargo.toml: {:?}", e);
-        }
-    });
-    let mut contents = String::new();
-    let len = f.read_to_string(&mut contents).unwrap_or_else(|e| {
-        panic!("Could not read file: {:?}", e);
-    });
-    println!("successfully opened Cargo.toml with unwrap_or_else: {:?}, contents {} bytes:\n{}\n----------", f, len, contents);
-
-    // using the '?' operator
-    match read_file("Cargo.toml") {
-        Ok(s) => println!("Cargo.toml contents:\n{}\n-------------", s),
-        Err(e) => println!("Could not open Cargo.toml: {:?}", e)
-    }
-
-    // using std API
-    match fs::read_to_string("Cargo.toml") {
-        Ok(s) => println!("Cargo.toml contents:\n{}\n-------------", s),
-        Err(e) => println!("Could not open Cargo.toml: {:?}", e)
-    }
-}
-
-fn main() {
-    test_strings();
-    test_vectors();
-    test_hashmaps();
-    test_files();
-}